GM 12 bolt questions

[67rstbkt]

I just picked up a GM 12 Bolt I hope that I can get to work in my firebird. It appears to be the Truck version; I base this on the shape of the Cover. It is not round like the car version. It's five lug and 57 inches from backing plate to backing plate compared to the 54.5 stock 10 bolt. Here are my questions:
Will I have a difficult time getting parts?
Are they the same as the car version?
I'm guessing that I have to narrow it to accomadate the mini-tub kit and wheels, Am I right?
Is there a draw back to putting this thing under a first-gen?
I'm planning on 500-600 hp and possibly some nitrous.
Any comments/help would be greatly appreciated.