BigBud: I put my plate on just a few weeks ago so I really can't tell you about durabilty og the tape. I can tell you that once you put it on, thats it! Mine is slightly off center (only I notice) and I couldn't get it off.
I've got a polished aluminum exhaust plate from West Coast Corvette. It bolts on and there are hex nuts on the mounting bracket that allow you to center it. A bit expensive (around $280), but the look is great.
One of our vette club members was rear-ended hard over the weekend (hard enough that it took the rear hatch glass, and destroyed the rear suspension geometery). We were looking at it and chuckled a bit noticing that his rear exhaust plate was still firmly attached! Mine has been on for six months and is completely secure. The tape is a 3M™ product, I think. I wish I could find out how to buy roll. The gaffer's tape of future! I could rule the world....
I made my own plate from some scrap aluminum I had laying around. Polished the aluminum and attached a rear hatch emblem on the aluminum. The plate secures to the frame with 2 self tapping screws. Total cost 20 bucks for the emblem. Looks as good as anything you can buy and I get to say I made it myself! 3M has really improved adhesives in the auto category and I wouldn't worry about using the tape.
I made an exhaust plate from aluminum and painted it body color. I used the 3M tape (Heavy-Duty Attachment Adhesive #6010ES) which comes in 3" strips and this holds very well. I have the template for the plate if anyone is interested in making one of their own.
i would be leary of the plates that tie the 2 exhaust pipes together because when you accelerate one pipe move upward and the other pipe moves downward due to the torque of the engine. clamping the 2 pipes together may put a bind or a strain on the exhaust system that could break or crack welds or brackets.