[madhatterpdc]

As far as I am aware, there is only one way to significantly improve acceleration, handling AND fuel economy...

Reduce weight.

I've seen too many people throw money, time and magic at a car and be disapointed with the results with no regard for the fact that the amps, subs, rubberized undercoating, neon lights, chrome rims, "spoiler" and fat chicks have over laden their car by an additional 200-300 pounds.

That's a 10% increase in weight for most cars, which would require a 20% boost in power to achieve the same performance. In other words, you are going to need a lot more than a fancy air filter and a carbon fibre shift knob to regain performance.

A perfect example is the new Lotus Elise. That car weighs just under 2,000 lbs and *only* has 190 hp. It is also regularly nipping at the heels of Ferrari 360's, 911 Turbos, and even F50's on road circuits. It is also rated at 23/27mpg. That is simply amazing for a car of this calibre. In a similar fashion the Ultima GTR weighs just under 1 ton as well and with a 680 hp SBC, can rip the 0-100-0 in 9.8 seconds, that's a full second quicker than a Ferrari Enzo that has about the same power, and the GTR has no electro-wizardry like launch control or paddle shifts.

Another physically sound way to improve gas mileage is by keeping the rpm's as low as possible. Try to stay in a taller gear and dip deeper into the throttle, the engine will only draw as much air as it needs and fuel will be metered as well to only meet the needs of the motor. I'm not doing this philosophy any justice, Patrick Bedard of Car and Drive did a decent write up on this topic several years ago in the context of an early review of the first Honda hybrid.