I've got a full MAC system on my 98 Cobra... LTs, O/R H, Dumps... works perfectly! Loud and mean.
The MAC LTs I've seen ruin the 4v motors are the ones whos owners get 'em and bolt 'em right up. Granted you should be able to do that with any part, but I never install any part on my car without a full inspection of the part before hand. Either way I got my headers JetHotted inside and out. That's probably what saved my ass if indeed it was/is weld slag causing the problems. Either way yeah I would say after all the money I spent on the MACs and getting them coated, I could have gotten BBK or even Hookers for less money...and they come already ceramic coated. Is that coating as good at JetHot? Who knows...probably...
In close I love my exhaust, but to tell you the truth if I had to do it all over I would not get MAC. Not that I have had any problems with mine whatsoever, they have been absolutely wonderful, but so many people with Cobras have been screwed, and coincidentally right after installing MAC LTs??? It's not worth the risk man. Experience may not be a fact, but it's worth somethin' I'm sure...