Wondering if there's any problem with tailpipes and the rear sway bar. I'm using the Firm Feel sway bar.

Mine had a full TTI 3" system on it when I bought it. No swaybar, but I can tell you that the tailpipes did rub the shocks a little. I took the tail pipes off and just use turndowns on the mufflers.

I also have a complete 3" TTi exhaust system on my '71GTX, and have not encountered the tailpipe interference issues you mentioned. However, this may be due to having cut off their welded hanger at the back end so I could slide on original type exhaust tips (for 3" pipes) and hook them into the correct hangers, just as they were attached at the factory. Adjustment flexibility of the factory setup is limitless compared with TTi's method.