John at
Air Cooled Engines Plus in Tiffin, Ohio
Google it if you need to call him.
He has a flow bench and specializes in VW/Audi. I had mine ported, polished, and complete valve job with swirl polished stainless valves for 550.00. That was shipped both ways. Gained almost double on the intake side for flow and 25% more on exhaust over stock.