how do you figure on the 97t ......its a medium glow plug .....have you ever run one ....or are ya just thinking its to hot ..... i have had good luck running them in medium plug applications ...on the other hand i have always had bad luck with o.s. plugs .....i think people run them because of there availability and nothing else ...as they are more expensive and dont last near as long .....just my .02 ....not trying to confront ...i just wanna get my hands on your secret glow plug heat decoder ring and yeh being that the prerun has no modding i could give 2 dumps weather its accurate or not ...im sure the extech will do well