Exhaust system question

[turbotodd]

1993 Mustang LX coupe.  I did a 2.3T swap and bought Stinger's 3" single exhaust system on the used market.  It also has a 3" down pipe, FWIW.  Anyway, I'm running into some challenges.  One, I can't seem to wiggle the 3" tail pipe in between the axle and tank.  On jack stands, I have about 1/2" or so clearance between the tail pipe and fuel tank rock guard.  That's really the closest area.  But it seems to rub in other areas too as I'm driving.  I drive daily and it seems to "rattle" against something different every day.  It's all held together with some Autozone style band clamps, not the saddle style clamps.  I forget what brand they were, but they were "unrolled" in the package and I had to assemble it around the pipe and then torque the snot out of them.  I got it all together and drove it a few days and it looks like the muffler has twisted, one side is considerably lower now than it was when I put it together; and of course I get the "rub" on the fuel tank (melted the rock guard).

Do any of you have any suggestions on this deal?  I'm pretty handy with a wrench but this one's got me frustrated....

[Stinger]

You have to start by using the correct clamps. Clamps that can be rolled/unrolled are for butt connected pipes (same size on both sides), not slip joints like mufflers and the pipes use. With the wrong clamps it's not holding in place so it's always going to move until it touches something/rattles.