WHEELS - Larger and wider wheels can improve handling by increasing the lateral g's the suspension can handle via the tires' wider contact patches. A wheel with a larger diamter will not only allow for bigger brakes, but will also have a lower profile tire, which can improve handling feel. It's a compromise between show and go however, in that the best wheel size for performance is probably no larger than 17". Be careful of offset, as it determines where the wheel sits within the wheelwell. This is especially important if you plan to tuck the wheels into the fender a little or install larger brakes. Wheels are either "cast" (cheaper and heavier) or "forged" (more expensive, stronger, and lighter). If you don't know the difference, buy some cast tools and see how they work out for you. And no big chrome wheels! TIRES - You can spend a lot of green on tires, especially if you buy OEM replacements or soft compound tires that need to be replaced more often. A common size for 17" rims is 205/40/17: the 205 is the tread width in mm, the 40 is the sidewall height or aspect ratio, and the 17 is wheel diameter in inches. Speed ratings are typically H (up to 130 mph), V (up to 149 mph), or Z (over 186 mph). Ironically, the more expensive tires usually last the fewest miles since they use a softer compound for better grip. Some of the most popular tires currently are made by Falken, because they offer high performance for a reasonable price. Drawbacks are noise and questionable if entertaining wet traction. BRAKES - It doesn't make a lot of sense to increase your car's ability to go fast without increasing its ability to stop. Brakes turn kinetic energy into heat. The larger the rotors are, the better they can dissipate this heat and prevent fade. Aftermarket rotors are available in most stock sizes, plus several manufacturers are now offering big brake upgrades that use your stock calipers. For those with the cash, Brembo and others make full conversions that use calipers with more pistons. For those on a budget, even replacing the brake pads can make a huge difference as long as you don't mind lots of brake dust. You can also try using larger brakes from another model made by your manufacturer. COILOVERS / SPRINGS - A coilover consists of a spring, a shock, and a threaded collar so that the ride height can be adjusted (adjustable height MacPherson strut setups are also available and usually called coilovers as well). Many units are made using a combination of off-the-shelf parts; some manufacturers offer fully matched components. Bump stops are upgraded polyurethane pieces on the more expensive units. If money is an issue, most companies make replacement springs that can lower your car using the stock dampers. A drop of more than 2" using only springs will likely cause the stock shocks to fail prematurely, however. Another possibility is a coilover conversion (usually called a coilover as well) which includes just the collar and springs. Many have more problems than full coilovers but cost a fraction of the price. A nice compromise that is popular with the track guys is the conversion kit made by Ground Control, which uses custom rate Eibach springs and Koni adjustable shocks. Be sure to research the spring rates that are best suited to your situation. Too high of a spring rate in the rear can make the car a handful in the twisties and on offramps. Too low of a spring rate in the rear will have you plowing through the corners. SWAY BARS - Sway bars, or stabilizers, minimize vehicle rolling during cornering by creating a spring-like effect due to the bars twisting. A car with larger sway bars will corner more flatly, plus the bars can be used to dial in understeer or oversteer. Upgrades are available from many companies that increase the size of the bar/s, but don't make the rear bar too large or the back end of the car will come around a little too easily for less experienced drivers. Obviously the rear bar goes in a little more easily than the front since there are fewer installation obstacles. The relationship between spring rates, damper settings, and sway bar thickness is a delicate one, so be sure to do your homework before hand. BRACES - Many cars now come with a strut tower brace, while some have tie bars in the rear of the car as well. Braces help maintain the structural rigidity of the vehicle, thereby helping the tires keep their contact patches on the road. They are available for the front and back, with the rear ones available in two styles on many vehicles. One is mounted on the top of the rear towers, similar to the front brace. These bars may interfere with your giant subwoofer box, though, if that is important to you. The other mounts below the car between the two lower control arm mounts. This is a fairly straightforward install, plus it is visible to other drivers who may be scoping you out as you cruise the mall. MOUNTS / INSERTS - One of the main problems you'll discover when adding power to a FF car is that the stock engine mounts are fairly flexible, which is why the car idles so smoothly. It's also why you can sometimes hear that loud WHOOSH sound during hard shifts as the header pulls away from the catalytic converter and why the wheels wil sometimes hop when the tires spin. Motor mount inserts, made of polyurethane, fill in the gaps left by the manufacturer. Full replacement motor mounts are also available. They can also prevent torn mounts, which will eventually do nothing for idle and ride quality. Full replacement suspension bushings are also available.