rear end ratios? (semi trans question)



i have been seriously looking into swapping my rear from a 7.5 to an 8.5 (if i can find 1) and wondering if with a 2500-2600 stall converter on a daily driver if id be better off w/ 3.55s or 3.42s vs. my current 3.73s peg leg? i do love the cruz w/ the gears @ 45 mph 2500 rpms in drive and off the lights i hook great but sometimes wish i could be better. would a higher gear ratio help more (seeing as the gn came w/ 3.42s stock w/ a 2200 conveter and a monte ss came stock with 1800 stall and 3.73s). any thoughts on this? heat wise? launchwise? and gas milage i no will be better but i do good now and launches excelent from a 50 mph roll.

p.s i almost forgot if needed my cam is a 212/222