pure atmospheric valves have issues with the golf, keep throwing out error codes, can get a forge r-splitter valve, which is 50/50 recirc and atmosperic, but apparently it hits performance. With the forge 007p valve which is just recirc, its pretty good, not alot of noise of noise but u do hear it going vrrrrr psssssss, not very loudly, but mainly in 2nd gear from my experience.
Pretty sure turbo flatter is not a good thing to aim or, thought it also causes more turbo wear, also I thought the DV has an effect of turbo flatter. One friends DV in the golf was fualty, that flattered, then another friend in his seat leon k1 mk2, changed the DV to a atmospheric one, which is just one with holes, that caused flatter. But when he switched back to stock the flatter stopped, wonder if the lower spec springs on the 007p will do the same by not holding pressure? Just an idea.