The exhaust system will not make a difference in the judging of your car in a survivor class IMHO. Even paint only has to be 85% original IIRC?

If correctness really is a concern, get repop pipes and hang the two NOS mufflers on there or get repop mufflers and paint them black to appear NOS. Unless someone crawls under there to check the date code on the mufflers, I think you'd be ok. And as Scott mentioned, and I'm sure you know to do this, keep the original system stashed, so it can go with the car if it's ever sold.

PS- I LOOOOVE your 2 T/A's!! My first T/A was an FY1- Mr.Norms car. I really miss that car