If you dont have a cool air intake or any kind of air intake you can make it sound good and here is how. Connected to the air box there is a tube. Take the box apart so you can get to the tube. Pull the tube out and there you go a loud sounding engine! There is nothing wrong with this. Wont hurt the engine at all. May sound dumb but it works I did it to my car, but now I have a cool air intake comming so im not worried about it.
The tube silences the air flowing into your box, so when you remove it it sucks the air in faster and makes a low rumbling sound. It also adds like 2 hp(wow haha! but its free). Whats weird tho is you can only tell when you accelerate at a high rate. Cause you dont suck enough air in when you just rev it up. It sounds sick when the engine is cold lol.
In the GT it will hurt low end torque and throttle responce.
Vibe GT, TRD springs, Progress bar, STB, Unichip, Borbet E 16x7.5, 225/50 Bridgestone RE750, beefed up grounds and battery bypass capacitors(had em laying around)
its definately the air silencer but there is also a big box that you can take off.. you'd be suprise what's under ur car!
My Car, with the kit on. it looks awesome! come and check it out, tell me what u think.P.S. the gray will be painted momentarily http://www.cardomain.com/ride/514882/1