You just have to exercise a little judgment.

If you’re old enough, you’ll remember how much fun it was to modify engines for more performance in the days of points, carburetors and leaded gas.

Now, of course, everything’s different. The Clean Air Act contains very specific language about what you, as an auto service professional, cannot do to a customer’s car, and mentions very substantial fines. Then, there are state and local laws, which may be even more stringent.

You can’t take the risk of flaunting these regulations, thinking that nobody ever gets caught. We’ve talked to people in the custom exhaust business, for example, who’ve been visited (and investigated) by armed Federal Marshals.

Then there’s liability. In these litigious days, you sure don’t want to do anything that has a dramatic effect on the dynamics of a vehicle. A little tweaking is probably safe, but if you make it into a screaming multi-hundred horsepower beast and there’s an accident, there’s the possibility that a lawyer would say that you made the car exceed the capabilities of its brakes or suspension.

All that said, there are quite a few things you can install that have no bearing whatsoever on emissions, warranty, or safety, yet will make you a hero to certain customers. Take SPT’s (that’s Subaru Performance Tuning — the line of parts available through your local Subaru dealer’s parts department) short-throw shifter, for instance. Whether for five-speed or six-speed transaxles, it gives the car a crisper, sportier feel, yet would require a mechanically-inclined person to install it. That means it’s the ideal job for you.

Another popular area that is unlikely to expose you to any risks is motor and transmission mounts, and “dog bone” links (called “Pitching Stopper Rods” in the catalog). The rubber in the SPT items is on the order of 10 times harder than stock, which minimizes engine and trans movement when you’re driving vigorously. This improves shifting and gives the whole vehicle a tauter, firmer personality. Once again, the risk of any liability is low.

• Stiffer transverse link bushings for tighter, more responsive handling.
• All kinds of sporty suspension components from WRX lowering springs to improved links and thicker anti-sway bars.
• A turbo boost gauge that mounts conveniently on the side of the steering column.
• Really cool shift knobs in titanium or carbon fiber.
• Stainless steel pedal pads with cherry-red rubber grips.
• An STi hood scoop that rams almost a third more air through the intercooler.
• Low-restriction mufflers and cat-back exhaust systems that improve power while enhancing the exhaust note. Sporty looking, too.
• Ground-effects and strake kits.

Other items available for end-user installation only (do to possibly bringing the vehicle out of compliance with safety/emissions standards and which are intended for off-highway application only) include:

• A low-stretch STi performance timing belt that cuts valve timing error from 1% (that can represent over three degrees) to .07%, which should make it popular with those who want to wring every last horsepower out of their boxer engines. It carries a 62,500-mile (100 km.) replacement recommendation.
• A stainless mesh clutch hose that resists bulging for more precise clutch action, and looks great to boot.
• In the same vein, a set of stainless mesh brake hoses that inhibits expansion under severe braking, and has a polyolifine coating that prevents dust and ice accumulation.
• A high-volume air cleaner element that’s a drop-in replacement for the stock unit, yet flows up to 30% more. No oiling required.
• A high-temperature red silicone air duct hose that connects the intercooler to the intake plenum — besides dressing up the engine, it won’t blow off under high boost.
• Several different clutch sets that can stand the gaff of hard acceleration with hopped-up motors. Add a lightweight flywheel for quick revving.
• Strut tower braces in steel and carbon fiber. These reduce strut deflection to promote quicker steering response. There’s even one for the rear.

And those are just some of the neat items in the SPT line. Check them all out at www.SPT.Subaru.com

NOTE: There’s still some debate about how custom wheels/tires of different diameters and/or offsets from stock will affect ABS and stability control. So, exercise caution here.

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