I bought this valve as a replacement for an HKS SSQV, which broke (apparently the plastic internals on the SSQV are not that sturdy). It holds boost effectively (my vehicle peaks at 21psi) with the yellow spring installed, and the sound is sporty but not too loud (my SSQV could be heard about a block away!). I would consider it slightly louder and a little more high-pitched than the OEM Bosch product with the diverter hose removed. Overall, the build quality seems excellent and I would highly recommend this product for a moderately upgraded SAAB or even a stock one if you want better throttle response or sound.

Rating: [5 of 5 Stars!]