This is totally hear say, but.
A fellow I know races around the state and has or had an extech 21, dont know if it was modded or not, but. The rumor is that he flipped or something and broke all the cooling fins off except for 2 or 3 within the first 2 or 3 mins of the race. He went on to finish the race, think he did well, but, everytime he pitted, the pit man took temps. hear say is that he ran at 400+ degrees for the duration of the 30 min race.
To me thats a pretty good indication of the quaility.