I had a question about 98 900 SE Auto. Im trying to figure out if I have a boost leak. I have a mbc from smartperformance.net. Just an MBC (not the +A). My question is that it boosts to 12 psi and holds it for a second then it slowly drops to 10. Is this normal since it isnt get a good air source like the +A does with the throttle body tap.