AR in LO. They don't specialize in Mustangs but they support local track guys. Another non Mustang focused shop and I've never been: http://www.preracing.com
Brad's in WA is where a few of my Mustang buddies go.
I used a "borrowed" open face model for a charity drive. I liked it. Am sure there's safety difference between the two. Just my guess and am sure others will chime in.....Prob not ideal if you're not fully secured in your seat via 5/6pt harness and less fire protection.
Fit is by far most important. Then visibility, price, weight, features, looks etc. My first helmet (and only so far) is a Bell M4. I tried several other brands before buying the M4. Am happy with it.
I have taken my R wheel to a local high-end bicycle repair shop that does very high-end CF work. Looks totally repairable. As EF300 pointed out, there some special filler and resin for CF. GL! Report back!