[Jake]

I have tried the 15" BFG's, Yokahama's, and BB"s. I love the look of the BB's but I did not like the way they drove on the street. they are really sticky when they get warmed up and I loved them on the track. The down side to having sticky tires on the street is they pick up all the rocks on the road and I was afraid of starring the fiberglass from the bottom-up. I did also experience the hunting on surface streets.
The 15" BFGs are pretty good, though they are not the best for traction. They are sometimes hard to get balanced so you don't get a wobble in the steering wheel. I actually had to have mine balance on the car which helped the issue. The 15" Yokahama's seem to be a better tire then the BFG's and I have no complaints with them. I have 17" Sumatoma's on the car now and they have a bit stiffer ride, but perform very nice and they are about $100 a tire! no balance issues either. There are two down sides with 17's that I can see. They don't look traditional if that is your thing and they do not make the correct tire size anymore to get the 27"-28" height. I am running the 315-35's on the back and they just don't fill out the wheel wells like the 15's did. I am hoping that someone will start making a 335-40-17 or a 315-45-17 by the time I wear out my Sumo's. They used to make a Good year F1 Supercar that was the correct height but it was discontinued a few years ago. They even discontinued the Michelin Pilot Sports that I liked.
The other thing I noticed with the 17's is they don't have the sidewall bulg that you get with the 15's, and that also impacts the look of the tire filling out the wheels wells. they almost look like they are the pushe a bit to far into the wheel well and they need a spacer. If you can afford it get both 15's and 17's and switch back and forth.

My 2 cents, Jake