if youre going to be going turbo's, you will w/o a doubt run out of gear in the 1/4 with any more than a 3.42.
I guess it really depends on what tire you're gonna be running. On motor, my car makes 430/430, and i run a 26x10x15 DO5 Hoosier slick. I trap at 120-123 and i am through the traps at 6900rpm with a 4.22 gear. With nitrous the car would be bouncing off the 7k rev limiter way before that.
With a decent turbo setup, you should be around 500+or- depending on the setup. That means you are gonna need a 27or higher tire to hook it up at all, and i'd stay around the stock gear, but wouldnt think to go and bigger than that.
You ought to look into chromoly driveshaft's. Carbon fiber is for show, chromoly is for go. Go to the ls1technationals when its near you, and see what kind of Driveshafts those dudes area all running=Chomoly
For shocks/springs, do it once and do it right, you need at least HAL QA1 F series, preffereably R series if you're a 1/4 guy. I run the F series and they are awesome. I had eibach's on the car, and the rear started sagging, and allows for no adjustment. The QA1's are adjustable height, and 12way adjustable shocks.
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