I just got a set of Avon's, they are being mounted today. They are replacing BFG Radial T/A's. I'll post later on how they perform.
Based on my research into the available 15" street tires (the sole criteria of which was performance, not looks or authenticity), I would say the medium priced alternative is the M/T Street Radial. If you can deal with the price, the Avon's are supposedly the best performing 15" street tire. The only complaint I have heard about them (aside from the price) is that the soft-ish compound picks up pebbles.
Based on personal experience, I would totally avoid the BFG's. I have put almost 20,000 miles on mine in 6 years of driving, but you would never know it to look at them. They wear like iron. The question is, do you want to drive on tires that have a compound so hard that they never wear out? I have driven them in all kinds of weather. Below 65F on a damp road, you're asking for trouble, such as on a fall or spring morning here in New England. In heavy rain, mud or snow they are not too bad, they have a very deep tread pattern which compensates for the very hard compound. The bottom line is: I don't trust them anywhere near the limits.
On the plus side for the BFG's, the car sits on them all winter and I have never had any problems with flat spots. They balance nicely and seem to be round. As one person observed in another thread, they are a great "build" tire
Roger Kraus Racing has a very nice cobra page that you might want to look at:
CobraTires.pdf