gashuffer, with the design of the head on the Ninjas, the exergen is closer to the plug than other heads. DO a little test, get the engine up to temp then take a temp with it down in the head and then raise it to where it would be flush with the top of the head. You should see a 30 degree change or so. That difference is why people say run it at 270ish because when you take that change away it drops it down to about 240(if a normal head was used with a hole that the temp probe wont go into) which is where most other engines run at. As long as you have smoke coming out in every corner and you still see a slight haze at the end of the straight at full speed, the temps are not a worry. Only time they should bother you is if they are unreal high, like 350+ and there is no smoke coming from the pipe exiting corners or at top speed.