what a difference!

[xxxBlakexxx]

It's your car. Make it the way you want. Everyone has different goals and situations.

Catbacks can add measurable power. There is some great info at Mach 1 registry where three different catbacks were tested on an otherwise stock Mach 1. SLP and Magnaflo were two of them I believe. The gains were 8 - 12 hp as I recall.

Plenum and TB combos are a proven 10 - 12 hp. There has been tons of studies done on these...it's a no brainer. You have to decide if the $350 for both is worth it.

I also must agree that gears such as 4.10's are a great mod. They will make the car feel more like a 5.0 by adding power down low and make the car scream that much more at peak.

So, here is a list of common mods, price and hp gains:

1 - Catback...$300 - $500...10 hp
2 - Under Drive Pullies...$200 installed...8 hp
3 - Plenun/TB...$350...10 hp
4 - CAI...$80 - $250...0 - 8 hp
5 - 4.10's...$500 installed....0 hp (but seems like 40 hp)