RE: ntc3 + O.S. 18tz = ?
The .12 would be a good idea if you are planning on racing formally because the NTC3 is a very solid racer. If you are just bashing, go for the .18 CV-R. OS makes very good motors that will last a while. I have a .12 CV-R in my GT and it has more power than I need. I couldn't imagine the power of the .18 CV-R. I know from real racing experience there is such thing as too much power which would definatley be a problem with the TZ. If all you do is sit there and spin the tires, you will never win a race. With more power you will also run into drivetrain issues and excessive tire wear. Definatley go with the .18 CV-R. You won't regret it.