10 Bolt-On Mods for the 4th Generation Mustang

1998 Ford Mustang GT

In 1993, Ford unveiled their all-new 4th-generation Mustang, regarded internally as the SN-95. The SN-95 served as an extension of the brand’s already iconic Fox-body platform, further building upon earlier technical advances, in a bid to enhance the Mustang’s overall performance acuity. By all accounts, these efforts proved successful, as the SN-95 quickly gained notoriety, and became a favorite of consumers the world over.

Though already quite potent in its stock state, the fourth-generation Mustang has become a popular platform for modification. Aftermarket parts are extremely plentiful for the SN-95, and a wealth of data has been published regarding real-world gains stemming from a wide range of modifications. This poses more than enough reasons for the mechanically adept to take the fate of their fourth-generation Mustangs into their own hands.

The following are 10 of the most popular bolt-on mods for the 4th-generation Mustang.

#10: Cold Air Intake

Ford Mustang Cold Air Intake
Credit: performancechiptuning.com

There are few better upgrades for the budget conscience gearhead than the installation of a cold air intake. This stems from the fact that cold air intake kits can be purchased at a relatively reasonable price, yet actually provide noticeable performance gains. Even more impressive is the fact that many cold air intake systems can be installed in less than an hour using only basic hand tools.

Cold air intake systems prove effective due to the underlying correlation between air temperature and oxygen density. As a general rule, the cooler the air, the higher its rate of oxygen saturation. Cold air intake systems pull cooler air into an engine’s intake manifold, thus enhancing performance. In fact, the bulk of manufacturers claim that their cold air intakes yield average performance gains of 5–10 horsepower.

#9: Aftermarket Throttle Bodies

Ford Mustang Throttle Body
Credit: speedwaymotors.com

The throttle body serves as a gatekeeper of sorts for your engine’s intake. Within this assembly is a throttle plate, which actuates in response to accelerator pedal input. However, the amount of intake air that an engine can accept is effectively limited by the total diameter of the throttle body itself. For this reason, many fourth-generation Mustang owners opt to purchase and install larger-than-stock aftermarket throttle bodies.

Those contemplating such a modification are in luck, as a significant number of aftermarket throttle bodies are currently offered for the SN-95 Mustang. These throttle bodies are offered in a number of individual diameters, allowing consumers to select the particular unit that best suits their particular needs. Modifications of this type often yield performance increases of 5–10 horsepower.

#8: Tuners (Programmers)

Mustang Tunes Programmer
Credit: totalzparts.com

Little brings a modified Mustang to life quite like the implementation of a custom tune. Tunes, or custom operating parameters for the PCM, can be written to achieve a number of goals. For most, this includes squeaking a few additional horsepowers out of their car’s engine. Uploading a custom tune can also maximize the benefits of other modifications that have already been made to your fourth-gen Mustang.

Tunes are generally uploaded through specialty devices known as programmers, which tap into a vehicle’s OBD-II communication network. Upon accessing this network, custom programming is uploaded directly to a vehicle’s PCM. Many of today’s programmers come preloaded with several generic tunes, though one can also download or write custom tunes of their own.

#7: Headers

Ford Mustang Headers
Credit: andersonfordmotorsport.com

Most stock exhaust systems, including the one found on the fourth-generation Mustang, are naturally restrictive. This, in turn, presents a certain degree of backpressure, which ultimately robs an engine of performance. Without being able to efficiently expel spent combustion gasses, an engine’s output is effectively limited. In turn, this also limits potential performance gains yielded from additional modifications.

Luckily, the issue of excess exhaust backpressure is easily remedied, with the purchase and installation of a set of custom headers. A wide range of aftermarket headers is available for the fourth-generation Mustang, most of which are significantly more free-flowing in nature than the SN-95’s stock exhaust manifolds.

#6: Cat-Back Exhaust

1994-98 Cat Back Exhaust
Credit: mrbodykit.com

Another popular fourth-gen Mustang mod involves the installation of a quality cat-back exhaust system. Exhaust upgrades of this type remain popular for the same reasons as those mentioned above in regards to header installation. These modifications expedite the expulsion of spent combustion gasses, thereby reducing the total load on an engine. This, in turn, often equates to a recordable increase in performance.

Cat-back kits typically include all-new exhaust components from the catalytic converter, rearward, such as mid-piping, mufflers, and exhaust tips. Consumers can also choose the perfect cat-back exhaust kit to meet their needs, as there is no shortage of such packages available for the Mustang. Best of all, cat-back exhaust kits also have the tendency to liven up the Mustang’s tonal characteristics, providing quite the aggressive exhaust note.

#5: Pulley Conversions

Ford Mustang Underdrive Pulley Kit
Credit: cspracing.com


All fourth-generation Mustangs feature engine-mounted accessories that are belt-driven in nature. In most cases, these accessories are driven by the same drive belt that traverses an engine’s crankshaft pulley. Though accessories of this nature are essential, they do present a certain amount of parasitic drag upon an engine, thereby reducing performance and measurable output. For this reason, a significant number of Mustang owners opt for the installation of underdrive pulley kits.

Kits of this nature typically include larger-than-stock accessory pulleys, and abnormally small crankshaft pulleys. This, in turn, overdrives the engine’s crankshaft, while underwriting all accessories. The result is the relative elimination of parasitic engine load, and a noticeable increase in engine performance. Furthermore, kits of this type are widely available and can be sourced without issue.

#4: Performance Disc Brakes

1998 Ford Mustang Disc Brakes
Credit: carid.com

A modified Mustang should not only power down the track with ease but should also be capable of bringing itself to a halt with equal efficiency. For this reason, many fourth-generation Mustang owners opt for the installation of upgraded disc brakes, which exceed the stopping power offered by the SN-95’s stock pads and rotors. Luckily, a number of options exist for those already eyeballing this mod.

One of the most popular options for upgrading the fourth-generation Mustang’s brakes involves utilizing brake components scavenged from the SVT Cobra’s of the same era. These upgraded disc brakes not only offer plenty of stopping power, but are also extremely easy to install. Factor in a relatively modest cost of acquisition, and this mod is truly a no-brainer.

#3: Aftermarket Dampers

Ford Mustang Coilovers
Credit: raceland.com

Few components bear such a heavy influence upon a vehicle’s handling and ride quality as suspension-related dampers. The fourth-generation Mustang serves as no exception to this rule, having come equipped with a less-than-ideal suspension package. For this reason, a number of SN-95 owners were quick to install higher-quality aftermarket shocks and struts.

Aftermarket shocks and struts are widely available for the fourth-generation Mustang and are offered at a widely varying price point. Additionally, shocks/struts are easily installed, with such a process seldom taking longer than a couple of hours to complete. Perhaps best of all, the benefits of suspension modification are immediately evident in most instances.

#2: Short Throw Shift Kits

Mustang Short Throw Shifter
Credit: cjponyparts.com

Certain modifications are as much about creating an enjoyable driving experience as they are about enhancing performance. Even better, certain modifications provide both benefits at once. This is precisely the scenario afforded by the installation of a short-throw shifter kit. Kits of this nature can also be installed without issue, taking little more than an hour to complete.

Short throw shifters significantly reduce the amount of manual effort required to shift gears, by reducing the gear-to-gear stroke. Because of this, those familiar with their transmission often find it relatively easy to reduce shift times, thereby resulting in quicker overall acceleration.

#1: Subframe Connectors

Mustang Subframe Connectors
Credit: globalwest.net

Over the decades, frame stiffness, or a general lack thereof, has served as a stumbling block of sorts for the Mustang. This problem was most pronounced during third-generation production when the Fox-body Mustang suffered from significant frame flex. Though a certain amount of this flex had been remedied prior to the SN-95’s release, the issue as a whole still persisted.

To relieve such problems in their entirety, a number of SN-95 owners have opted for the installation of aftermarket suffrage connectors. These tubular braces significantly stiffen the Mustang’s chassis, preventing undue stress. However, the biggest benefit of this modification comes in the form of enhanced handling capabilities.