caslaleenie....I have the same exact problem as dave semko with a steering vibration starting at 60 and getting much worse at 70, although my spf was delivered with goodyear gt II's. I only have 800 miles since I took delivery in December. I have not gone through all the balancing and tire swaping as dave but I know the goodyears are probably no better then the bfg's or maybe you guy's already knew that.
Tony