RE: Temp gun
Sight and sound are the best when it comes to tuning a nitro engine. I have 27 years in the hobby and have had a temp gun and radar for only the last 2 years. At some point you will get to where you just know which way and when to tune. I find the temp gun good for reference and teaching. It is also good for monitoring performance after you tune. Once you have your engine tuned correct, check the temp. It should stay about the same for the rest of the day. Any real change will indicate a change in the weather requiring a new tune, Air Filter needing cleaned, Or a problem such as an air leak ect..