Make sure that you have a goal in mind when picking an engine. For instance, I use a Xenon R on-road .21 in a NTC3 car and it hauls azz but for drag racing, I will use a Jammin .28 off-road engine because it makes gobs of low end TQ and HP for the 132' range that I would need the motor to operate in.

Xenon R makes 50 oz. TQ from 25,000 to 40,000 RPM's and peaking at 63 oz. TQ at 36,000. It peaks HP of 2.25 at 36,000 but by 40,000 it is 1.75 HP

Jammin .28 makes 50 oz. TQ from 12,000 to 36,000 RPM's and peaking at 85 oz. TQ at 26,000. It peaks HP of 2.30 at 26,000 and by 36,000 it is 1.40 HP

If the two engines were in the same type of cars and both cars hooked from a dead stop, guess which one would get to the end of 132' drag run faster? This is just my analysis of the two engines that I am dealing with though and just an example to gauge by when shopping for an engine's intended use.

Here's my NTC3 with the Xenon R on it

http://uk.youtube.com/watch?v=FW03UZ41GtU

BTW, I also have a .18 TZ and it is not as fast as the .21 motor is and both are bone stock from the factories. I do like my .18 TZ though and it too has an intended purpose but not for what I want to do with the NTC3 just yet.