What tranny do you have, 5sp or auto? If it's a 5sp and you're gonna stay n/a, don't go any more than 4.10's, if you want to do a power adder(nitrous/forced air) then 3.73's are a good choice. I run my car at the track n/a, 4.10's are good, I'm approaching redline at the traps in 4th gear...