Go with the Tc4 so if you break somthing at the track some may have the part. Nobody around here runs the trinity car so parts will be hard to find. You can pick one up at any of the following:
Rc barn in Hampton 651-437-9065
Rc Car King Burnsville 1-800-707-King
HobbytownUSa Oakdale 651-702-0355
Hub hobby Richfield/Little Canada 612-866-9575/651-490-1675