i took the vaccume line off my standard one and used just my hks one, and i found at low revs i was getting turbo flutter and my car was stalling, also at high revs it seemed to make no noise at all, then i took the vaccume line off my aftermarket one and just used the standard one, and it was farking loud PSCHHH... sounded like i was shifting at 7k when i was shifting at 4k, the car didn't stall tho
but its leaking boost so ill have to get a performance plumb back i think?