555's are a good all-around tire. You do have to heat em up to get them to stick though. I had the BFGs before, and they didnt last long. Scary on anything but dry good roads. I could use the 555s in any weather without problems. They will last longer too. If you dont drive on the street a lot, more of a track car, then BFGs would probably be better. But if you generally just drive it on the street, the Nittos are better for that.
I have the 450's on the fronts, and I really dont think they are all that great. They feel like they wander around too much. I had BFG Comp T/As on before, and they were twice the tire the 450s are. Worth the extra $$$.
Before I put drag radials on, I ran 245/50ZR16s BFG Comp T/As. Very nice tires. The 450s are a cheap tire, relatively hard compound. They wear long, but traction is not very good with them, plus they track the small changes in the road surface, so they feel like they wander. I wouldnt even dare to use them on the rear, not nearly enough traction for my car.