Heck, this was the first time I heard of a stainless exhaust on a four wheeler. I just bought a 2013 trx450r and for all I know it could have one on it.  I by no means know what you guys do. Period. I'm just curious, so if I ask questions that come off like I am questioning you, please accept my apologies.  And I'm apologize if that post rubbed some of you guys the wrong way. So now come the peanut galleries' questions... 

1.  Would it matter that those are pipes are 4 pokes and not 2 strokes?

2.  What kind of problems are you seeing from the ones you have been fixing?

3.  Any ideas what is causing those problems and how to resolve those issues?