Seems like my GN is using quite a bit of oil. Is this normal with a moderate mileage motor? I mean my motor is nearing 100k miles but that isn't really that much...my car is using close to a quart of oil every couple weeks...it doesn't smoke oil or anything but I have to keep adding after a couple weeks...I am using mobil 1 synthetic 15w50 oil yet...with all these mods and big turbo is this normal to use oil like this??? i do get into boost almost daily so