Like has been said already, the gear change won't get you much. The 100 shot will pick it up a LOT and be a helluva lot of fun. Definitely the best bang for the buck. Bracket racing it w/ the nitrous may or may not be for you.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax