I know of exactly 1 (exhaust) shop in Georgia that has a mandrel bender. Given the 40K plus price tag I understand. I also understand that I'm going to have some work done - since there are endless engine, transmission, bed length, cab length, year variations, chassis / frame variations, etc.
That said it would be nice to have people share what they have done, kits, custom shops, challenges, etc. The sound may not be exactly as it is in the real world, but its is more accurate than no sound at all.
A great example is I have seen that Pypes offers a 409 stainless crossmember back. I cant seem to find anyone who has this kit - regardless of motor. I also cant find a sound clip for any of the 3 muffler options, I cant find thoughts on quality / construction, and I cant find challenges that may have run into like crossmember clearance. I do see that 73-87chevytrucks.com sells it. I'd accept a shameless plug / propaganda at this point.