I finally ran my first vta (cta in Canada) race yesterday, using a spec-r s. It was way more fun than I thought it would be. Coming from 17.5 touring, the cta cars are a lot slower, but makes them easier to drive. My cheap old Spec-R was posting the same lap times as the xray/ serpent/tamiya 417 v5, so it is nice to know that $120 chassis is adequate for the class. Is definitely recommend the class to any noobs interested in getting into on road. The bodies look super cool too.
I'd say the "S" series (spec-r) is the best for VTA, a little extra weight and flex. Both are good for VTA. The class is perfect for a wide range of chassis to compete
. I'm building an older Xray as a second car but I am also holding on to a TC3, which has been working fairly well for me.