Mitsubishi Eclipse Forum : “on a 2001 eclipse gt what would be an easy and cheap way to boost performance”

I've got three words for you: cold air intake.

but dont expect a MASSIVE "boost" in performance. CAI and other "breather mods" will help your top-end performance of the motor

http://www.autopartswarehouse.com/category/engine_-and-_drivetrain.html   there you go buddy, pick something

I got a 2000 Eclipse GT and I just installed the K&N Typhoon cold air intake system on it, i can definitely feel the difference in the top end power. The car doesn't lag as much when you hit the gas. This works great if you also have some kind of aftermarket exhaust as well, I have a magnaflow catback on mine and it made it sound ten times meaner then it was.