Boxster High-Performance Suspensions

Street Suspensions

Optional Porsche Suspensions

I firmly (no pun intended!) believe in the optional M030 Sport Suspension. M030 replaces the standard springs, sway-bars and shocks with stiffer units. It's a high-performance suspension that is fully tested and warranted by Porsche. And I also believe that this option is superior to most of the aftermarket suspension lowering kits available. And M030 is legal for Boxsters in their SCCA "Stock Category" autocross class.

M030 was originally sold only as a part of the "P38 Technic Sport Package" on '97-'98 Boxsters, and included P37 Traction Control and 17" wheels as well. For the '99 models, Porsche made the individual elements available separately.

Lowering Springs

This has become a popular customizing trick. People really like the lowered look for sports cars. Many manufacturers have assembled kits that include springs to lower your car, which is a lot better than cutting the original springs like people sometimes did in the past. However, even these kits are not without drawbacks.

Most aftermarket lowering kits do just that: They lower the car, usually by 1" or 2" with a 10% to 25% increase in spring stiffness. But in my experience the aftermarket kits are often poorly tuned. Unless there is an increase in spring stiffness proportionate to the amount of lowering you will have an increased tendency to bottom out the suspension. This, in turn, can lead to damage to the suspension and chassis. Also, it's rather common for the spring rates to be poorly matched front/rear, and unpleasant (not to mention detrimental to handling) "pitching" or "porpoising" can occur over bumps.

But some people still want that lowered look, or have decided that they are willing to accept the sacrifices that go along with achieving even higher performance. This can help handling as well as looks, but you have to do it right. So if you really want to go that route, check out some spreadsheets I wrote that can help you calculate and design optimized suspensions for cars on my "DSP Suspension Design Software" page.

"Street Prepared" Suspensions

If you use aftermarket springs and sway-bars your car ends up competing in its SCCA "Street Prepared Category" class, and to be competitive in SP you'll likely also have to modify the engine for more power and make even more radical changes to the suspension. The car may lose warranty coverage and be unsuited for street driving (and probably no longer be street legal).

Struts and Springs

For the ultimate in handling, but at a considerable sacrifice in ride quality and money, you should buy what is commonly called "coilovers." These are struts (sometimes also called "coilover shocks") that are similar to the standard Boxster struts, but also have a threaded body and spring perch that allows very easy adjustment of the ride height. They also generally use standard racing springs which are available in countless lengths, diameters and rates so you can fine-tune the suspension to work best with your car. Turbo Performance Center. sells coilovers for the Boxster, as does Gemballa, though they can also be custom ordered straight from a place like Truechoice with Koni struts custom valved to match the spring rates you choose. Truly impressive hardware, but a lot of work and money. See the software I mention above for help in determining what the spring rates should be for your car, or rely on the advice of the people who sell you the coilovers.

If coilovers are too much for you, you can instead buy aftermarket springs that fit into the same location on the struts as the original springs. Eibach and H&R are common brands that make springs to fit the Boxster. I recommend using the struts from the optional M030 Sport Suspension instead of the standard Boxster struts, since the stiffer springs really need stiffer strut valving to complement them. Until recently the only way to get stiffer aftermarket struts was to use coilovers. But now you can also have your standard Bilstein struts (as installed from the factory) re-valved. I don't know all the details, but I believe that calling Bilstein USA headquarters would get you the info needed.

Sway Bars

Also known as "anti-roll bars," "stabilizer bars," or "anti-sway bars." There are now at least two sources for aftermarket sway-bars for the Boxster: Fordahl Motorsports in Bellevue, Wa. (425) 644-6020 sells an adjustable front sway-bar, and Gemballa sells a front/rear set. Contact Jamey at Paris Audio, he can give you all the details about the Gemballa sway bar: 310-289.8494. It used to be that the only alternative to the standard sway bars were the bars from the optional M030 Sport Suspension. If you want bars even stiffer than those you'll have to fabricate them yourself, or have somebody fabricate them for you. I've had good luck in the past using "modular" sway bars from Speedway Engineering which can be bought in various lengths and diameters, and even as tubular bars. You then have to fabricate the necessary brackets and end-links to mount the bars to the car. See the software I mention above for help in determining what the sway bar rates should be for your car.

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