The KDW2 only comes in 24" OD (205/50, 225/45), but is a great tire. It's a bit expensive, at around $120. The Azenis and the MX are good, but not the best in the rain. The MX is better than the Azenis in standing water.
The Hankook Ventus R-S2 Z212 is nearly as sticky as the Azenis, with better wet performance and ride. They're $95 each shipped from
http://www.discounttiredirect.com.
The Kumho MX wears better than the Hankooks and is about $95 each shipped from
http://www.tirerack.com. Decent in the rain, and 225s will grip like mad in the dry.
The Falken Ziex ZE512 is nearly as sticky as the Kumho 712, and only $72 shipped from
http://www.discounttiredirect.com. They're well below the MX and Z212 in dry grip, but pretty close in the wet. Treadwear is similar to the MX, from what I've seen.
The KDW2 is between the ZE512 and the MX/Z212 in the dry, and among the best in the wet. But you pay for it.
You really can't go wrong with any of those tires, but I'd bet the 225/50R16 Kumho MX will be the best deal for you. The dry grip is astounding, they wear well, and the price ain't bad. I have very little personal experience with the Hankooks, but from what I hear they will have better wet grip, similar dry grip, and worse tread life than the MX, for the same price. You also have a choice of 45 or 50 profile tires in the 225 width with the Hankook.
No matter what you get, post up and tell us what you think!
EDIT:
Oh yeah, the Goodyears and Avons. The GS-D3 is similar to the KDW2, with better wet grip. They're also quite expensive. I don't feel they're worth the premium unless you are after wet grip as a major priority.
The Avons are similar to the Fuzion ZRi, Kumho SPT, and others. These are the new generation of tires like the 712. They last at least as long, handle better, and stick better than the 712. They have similar grip to the ZE512, in general, most I've driven are a bit better. The ZRi is quite sticky, but has a lousy carcass. The SPT is supossed to be quite good. But, you will sacrifice a healthy dose of dry grip to save money with these tires. I'm around two seconds per lap faster on the autocross course with MXs vs. ZRis. That's not huge, but it's noticeable on the street. The MX is a much nicer tire at the limit as well, and it wears better.
