As much as I've read into the matter, the answer is no, as long as your able to restore your stock tune, you should be fine. I will either get a custom dyno tune or a diablo sport tune with the aid of TED or Lew. I am just waiting on my Camaro to let me know its ready. A check engine light (CEL) is what I'm waiting on. 400 miles on my long tubes and no problem. http://www.camaro5.com/forums/showthread.php?t=58363
Thousands have already tuned theirs, go with a reputable tuner and have the ability to put the stock tune back if the need arises. I will more than likely go with a Diablo sport due to this fact and a boatload of hand helds out there give you a 93 octane tune but can't dial in extra hp for your long tubes.