Pretty much all the 1/12th cars on the market now are excellent so go with what you can get parts support for. The 12r5.1 is great. I like the CRC GenXL, it's very well priced and easy to get parts for. If you want the latest high tech rig, the BMI looks awesome.
Most everyone is running brushless and lipo now but check with your track to see what they are running. For brushless, Tekin RS with a Tekin or Duo motor.
Sean. Certified speed crazed mowron.
Team Shepherd USA