Yea your definately new
, i assume your talking about "3.5" as 3.55 ring and pinion rear gears, these are not stock, however, not much more performance than stock, although they help, yes a 3.73 gear ratio would workout for street/strip.
I have an ads chip, but you would be better off putting that money elsewhere, also, your car should not be "reprogramed" unless your getting a custom chip burned for heavy mods wich you obviously dont have.
the rearend may be worth it, but your better off getting some new motorsport gears, that way you have no chance of getting a whiney, or chattering rearend, hope ive been of some help.
good luck.....
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90 lx coupe: 5spd, energy susp trans mounts, fms hd clutch, Mac coldair fenderwell, Mac h-pipe, supercoil, ADS chip, 160 stat, aluminum D/S, Black magic fan, 3.27grs.
Best time: 13.9116(on 225/60/15 firehawks)
Best mph: 98.17
Best 60': 1.9607
someday mods:4.10's, slicks.