Here are my comments:
1) Depends on whether you want to run stock or street prepared. For street prepared, you want wheels as wide as possible. 13x8 and 13x9 wheels with 225 or 235 width tires are popular. For stock, you have to run the stock diameter and width. I think that the Heliums are 6.5" wide, so they're not legal. And in Kevin's case, the '94-97 wheels would only be legal on specific special editions from '90-93, since the standard wheels on those cars were only 5.5" wide. Your local competitors may let it slide.
2) For a long time, the only tire available in my size was the Kumho ECSTA V700. I think that they're pretty lousy. In their original (K8A, Victoracer rubber) form, they lasted about as long as Victoracers but didn't grip as well. They also developed a deep groove on the outer middle tread strip. When Kumho went to the softer compound which "required" shaving before use, the tires didn't last nearly as long -- about as long as Hoosiers! -- and still were only about even with Victoracers. They also hate being pinched onto a wheel that's too narrow. One of the Kumho contract drivers tried the 225/45-15 ECSTA on his Miata and switched right back to the 205s. Given the choice between the V700 tires, I'd choose Victoracers.
3) The new generation tires (V710 and A3S04) are awesome. Probably only good for about 60 runs on a Miata, but the A3S04s stick so much better than the V700 tires that it made me cackle with glee. The V710s are supposed to be right up there with them. The Hoosiers are no longer a "concrete-only" tire. Most of my use of them has been on asphalt, in fact. 205/50-15 is the only appropriate size available so far, but it's so wide that you'd have to be nuts to want to run anything wider. Mounted on stock wheels, 205 V710s are about as wide as 225 ECSTAs.
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. A local racer uses 225 Hoosiers on them with no complaints (I trust him too since he's first in class 95% of the time, heh). A 225 will fit on a 6" wide wheel with no trouble at all.
