You better do some more research and reading on this. Switching to a mustang II will likely drop the front of your truck quite a bit. Why not keep the stock straight axle, and get a disc brake kit that switches to 5 bolt lugs and you can run any 15" wheels you want.
Don't go for the "cheapest" IFS you can get, as some are surely cheap, but you get what you pay for, and it's a very important component of your truck.
Last edited by 46gmcpu; 11/27/2012 10:44 AM.