[Mr.ac]

It all depends how the bends are made.
If it's just a cheap old pipe bender then the flow won't be as good.
If they have a good mandrel bender then it's pretty much what every aftermarket header uses.

Not sure how good local shops are but, if he's into Motorsports and has a good rep for making dyno proven results then why not?
If it's just some hole in the wall muffler shop, eh, it's your call. Who knows.