Retune after Mac mids?

I'm currently running a 91 octane Soloman tune with a 52 mm TB and a magnaflow cat-back. I'm installing Mac mid-length headers and Y, retaining the factory cat. Do you think I'll be ok to run the car for a while (including a few autocross events) without a retune? I'd like to hold off until winter before sending the ECU back.

Yeah, you'll run fine without a retune with Mac's. You won't be making optimal power, but you're not going to lose any and don't run any risk of hurting anything.

I appreciate the input!