which 1/12th scale to choose?
The Tamiya car, once outfitted with all of the desirable option goodies, is very expensive and yet still not on the cutting edge of 1/12th scale performance. The Xray and the Serpent are both very good racing platforms, but also quite expensive. The CRC is the least costly of the more serious 1/12th scale chassis choices and plenty of them do well most every major racing event. CRC parts and technical support are really good too. The AE car and the TOP cars are also very nice offerings that are available at reasonable prices, slightly higher than CRC but significantly less that either the Xray, the Tamiya, or the Serpent. My advice to you would be to pick the one that is best supported wherever you plan to race it. The assistance and input from your local "fast guy" who runs any of these choices can be a hugely valuable resource.