From what I have seen, I will be doing the 3.27 gears in mine. Probably my next mod. If you know where to look, you can pick up a 3.27 Camaro LSD for less than $600. I have HP Tuners now, so that part won't cost me anything.
With stock gears, most people are barely getting into 4th gear at the track (1/4 mi). With 3.27's, they are using about half of 4th, and with 3.45's it seems like they are using most of 4th.
In 6th gear with stock 2.92 gears at 70mph, you would be running around 1800 rpm. With 3.27's, about 2000rpm, and with 3.45's around 2100rpm. The problem with 3.45's is that our 1st gear is so short (4.02), so 1st becomes almost useless without sticky tires.
I plan on more power in the future, so I'm going with 3.27s