Been following the post and just had the BD Scorpion S364.5sx-e kit installed with a FASS system. I have no experience with the other turbo and I can't really compare noise level in regards to whistle/whine but I see where y'all say how quiet it is. The reason I bring this up is because In this setup mine is fairly loud. Love the turbo performance wise but the consistent high pitch even at 2psi when cruising drives the family crazy. I'm good with it but already sick of listening to the kids complain. So to ease my mind could someone verify if this is normal or could something be incorrect with the install. Had a reputable shop do the install but they said this is the first time they have installed this kit.