I know a lot of forum members have been having difficulty with the Stillen Exhaust installation. If you are having problems getting the pipes to clear the cross member lower brace, the cross member brace bar thats at a 45 degree up higher, or having an exhaust leak. I want to try and give some tips as to what to look for and how to remedy the problem. Unfortunately I don't document my installs, so I don't have any photos.
Forum members with successful installs please feel free to add suggestions to the post and lets help everyone out.
The first issue most have experienced with the Stillen exhaust is that it was resting on the cross member. I do NOT believe it's a design flaw but needs a specific installation and knowledge of how to dial in the right placement.
I think in order to have he best chance for success it's important that you get access to a 4 or 2 post lift. Working with jack stands makes it really difficult to see.
If your exhaust is resting on the cross member, I suggest you loosen everything up starting at the cat brace in the front of the car working your way back towards the muffler. Get a floor jack and a piece of wood and jack up the pipes so it clears. Tighten everything up (don't forget to check your gaskets are in place), I recommend using air tools such as an air ratchet and get out your and socket sets. get everything nice and tight. Hose clamps will really come in handy to compress the rubber hangers so they don't stretch. Make those nice and tight. Lower the jack and see if it clears. You should have no problem. If it still doesn't clear it is possible to back out the 4 screws on the cross brace and use several washers between the car and the brace to act as a shim as another forum member did.
I installed high flow cats and sway bars over the weekend and had a rattle because my exhaust was hitting the cross member bar that forms a 45 degree angle off the brace or cross member because I had mine too high! I was so worried about clearing the cross member and it was 2am i couldn't see what the problem was anymore. Taking a step back from things and coming back to them always gives you fresh insight. I strongly believe it working with a friend who knows as much if not more whenever you do modifications. When all else fails take it to a shop and you still will of saved money because you did most of the hard work already.
In conclusion, if you have any doubts, your exhaust doesn't clear, you think you have a leak, take it to a mechanic that comes highly recommended. A lot of these people have been doing it for over 20 years. Most of us just turn a wrench a little here and there, don't get down on yourself, it's all a learning process. Hope this helps. If anyone has some pictures please post them so everyone knows what I'm talking about. lol I may have made up a few terms but with a pic or 2 you will know what I'm referring to. Good luck, be safe, double check, triple check everything.