You can find ls1's pretty cheap nowadays. But, speaking from personal experience (and I'm gonna say this at the risk of getting flamed up), I'd stick with the lt1. Yeah the ls1 makes more power, better mileage, and SOME think it looks better. But from my experiences, lt1's last much longer and can take more abuse. I've had 2. I have lots of friends with ls1's none of which have taken the abuse like my lt1s and my buddies lt1's have. But to each his own. And take care in Afghan man. Ill be there soon.
1995 Z28 M6 Vert:
3.73s, LPE Cold Air Intake, True Duals, WS6 Store Short Stick, ***-tons of weight reduction, and some Nittos to make her try to hook