Right now my Camaro has 235/55R16 tires on it, but it's time to replace them. According to the places I've talked to, that size is now incredibly hard to find, and as such will be pretty expensive to replace.
I've done a bit of searching, and it seems that 245/50R16 tires are almost the same size and that a lot of people have replaced the stock size tires with them.
I ran 245/50/16's before my SS wheels and I liked them. I still have them sitting on the stock rims, probably going to use them for autox. They were BFG g-Force Sports and I liked em a lot, and they are reasonably priced. Only problem is they are back ordered just about every where. Since I needed new tires pretty badly I ended up finding this set of SS rims with brand new Nitto 555's (275/40/17) for $700 shipped, which was "only" $200 more than the BFG's alone. The Nitto's cost ~$165/tire (for a total of $660 worth of tires), which made it to where I pretty much got the rims for free and just paid for the tires and half of shipping. And the 275's have made a world of a difference on the handling of the car.
Basically, look around locally and on ls1tech and see what you can find if you may want different rims. You may be able to find something for a little bit more (or the same price) and be happier w/ the end result. Especially if you bump up to the 255's, the price per tire on the BFG's go up $25/tire, so you are going to pay $550 + shipping for the 255's, or $450 + shipping for the 245's. Just something to think about.