Single turbo I assume - is that in stainless?
I very much see the point for getting it locally made by someone that knows what they are doing. There are many that don't, and usually the ones that will do it for next to nix.
I like the idea of HKS or Midori, or Racepace for that matter, in that it's likely undergone enough design and testing in-house before it made it to your car.
It's the little things getting custom work that *can* come back to bite you - cracks, vibration on other parts etc. Can quickly make the $300-400 difference in price no longer worth it.
The custom front pipe on my old Evo use to knock on the underbody bracing a little when turning right... pi$$ed me right off.