rule of thumb... 4.10 NA, 3.73 with power adder (supercharger/turbo), but ultimately, your choice. best seat of the pants upgrade hands down...

 

The 4.10s are very popular but lately people are switching to the 3.90s and 3.73s. Personally I believe you wold be happy with the 3.73s.

 

I switched my 3.55's out for the 4.10's. Much better for driving around town and it adds a whole new feeling of torque. It will also slow you down once you hit 40 cause that's where 4th gear wants to be. On the highway I generally drive 70-75 and 5th gear is fine, hovering between 2500-2700 rpms.

The biggest con to me is that 1st gear is useless. I find I shift to second almost immediately.