I thought some of you would appreciate the info from this wiki page. Matt gives out a ton of info on 4l80's and ls's. He basically shows the cheapest route to making 500 - 600hp with a turbo'd ls. He also has some pretty cool builds and a lot of good videos on youtube. Check him out.
https://sites.google.com/site/sloppywiki/everything-ls/sloppyguidejunkyardturbols
https://sites.google.com/site/sloppywiki/everything-ls/sloppyguidejunkyardturbols