Some of the cheapo parts store biscuits are quite a bit thinner than factory. And of a lower quality. Replacing them with the proper thickness may move your header away from the box. You could easily make some shims to put between the biscuits and the k member. All you need is some flat metal, a cut off wheel and a drill. Personally, I wouldn't trust the cheap rubber mounts as far as I could throw them. I prefer solid mounts as I don't mind a little vibration. There are alternatives though : http://www.dodgecharger.com/forum/index.php/topic,13216.0.html
I'll take a look at my biscuit mounts, They're probably a little worn out as they were on the previous owner's engine. I think I have some 1/8" steel plate laying around and I have a cut off wheel and plenty of drills so that shouldn't be a problem.
Schumacher usually shows where the engine should be located, i.e. it's factory location. I would confirm that first, then if you can move and/or shim things about till all clears. But it is not uncommon, even with TTI's to occasionally need to manually clearance the tubes (bash a dent in them). If you decide you need to go that route I'd look at how some do it with finesse, You tube video or similar.
I found the engine location guide per TTi's website. I'd rather not pursue the dent the header route as it has more manual labor involved, but we'll see what happens.
