1999-04 Cobra, Bilstein HD series damper package for IRS-equipped Mustang, includes 2 Bilstein HD struts and 2 Bilstein HD shocks, with integral progressive bumpstops. If you do not already have, or purchase now, an MM rear coil-over conversion kit, you must add urethane shock eye bushingsMMSM-105to install the grooved rear shocks in this package.
Included in this kit's price is a charge for grooving the rear shocks for a coil-over conversion. You can get a $40 discount if:
You purchase a rear coil over kit along with this package.
In the past you purchased a rear coil-over kit directly from us.
You purchase a rear coil over kit directly from us at a later time.
If any of these situations apply, please note it in the "special instructions" field at checkout. We will confirm the situation and waive the grooving charge when we process your order.
Struts are suitable for both stock-location springs and coil-over conversions. See chart below for spring recommendations.
Rear shocks are suitable for acoil-over conversion, as a groove is machined into the rear shock body.
For more details and technical information, scroll down.
Heavy Duty (HD) BilsteinSpring Recommendations
Conventional Spring Sets
MM Road & Track H&R Race H&R Super Sport H&R Sport Eibach Pro-Kit Stock Springs
Coil-Over Spring Rates
250 - 325 lb/in
IRS Rear Springs
475 - 525 lb/in
Firm, yetgood ride quality, as is expected of a performance car
Bilstein struts and shocks are made with patentedmono-tubetechnology
Invertedstrut design has very large strut shaft bushings for greater resistance to deflection from cornering loads, and protection of the oil seal
High nitrogen gas pressureprevents oil foamingand resultantfading
Monotube design has betterheat dissipationthan twin-tube dampers, keeps the oil cooler, and decreases heat-induced damper fade
Velocity-sensitive valving improves ride quality
Each Bilstein strut and shock istestedon a shock dyno
The Bilstein rear IRS shocks are grooved for coil-over conversions, and include an integral, progressivebump stop
Bilstein struts and shocks includedustcovers
MM Sport series and MM Race series dampers are better suited for moreaggressivespring rates.
Tech Heavy Duty (HD) Bilsteins work very well in street applications with a variety of both conventional springs and coil-over conversions. They are designed to deliver the best possible ride quality coupled with impressive street performance. The HD series dampers were not designed for use with overly aggressive spring rates, particularly in coil-over conversions. For dampers more suited to aggressive spring rates, see the MM Sport series and MM Race series dampers.
While they are non-adjustable, Bilstein's unique deflective-disc valve design instantaneously self-adjusts to changing road surfaces. Their performance does not degrade with age, usage, or heat, requiring no compensating manual adjustments as with other brands. Bilstein uses a patented mono-tube design that allows for a larger piston size than is possible with a twin-tube damper. The mono-tube design provides better heat dissipation to keep the damper's oil cooler, and decreases heat-induced damper fade. High-pressure nitrogen gas prevents oil foaming and fading. The unique inverted design of the Bilstein strut allows for very large strut shaft bushings, which are less prone to deflection. The inverted strut design also keeps the oil seal protected from the elements. Every Bilstein damper is tested on a shock dyno before leaving the factory to ensure quality.