All bull crap! I change my spark plugs no problem... Compression check no problem.. I've had my headers on for 5 years and not one scratch on the bottom of them....
even if I can directly look straight at my spark plug I don't try and change it when it's red hot... Who the hell does that.,
Truly the issue here is the manufacturers quality control and the minor variance between header makers. Even though they all look the same, some do hang lower than others.
