I got one of those Chikara Headers, went to put it on and the bolt holes didn't match the studs... My wife got me a Chikara dipstick (for my birthday) and it doesn't fit with the lower header heat shield in place...
Baaaah!
I did leave the factory header on w/o the heat shield and no problems, yet.
AND.... The thing that really pissed me off is that I got it on backorder from Summit, meaning I had to wait and wait and wait for the damn thing to get here and it didn't fit.