I had a custom h-pipe installed as well by a local shop, that I have been going to for 20+ years. Paid $450 CDN with tax. Buying an h-pipe online would have cost me more and I still would have had to get it installed.
I put Powerstop Rotors, and pads, on the 2019 Mustang GT I had. They looked and performed great. Can't speak to the longevity of them as I did not keep the car for long.