difference on gas mileage and maybe some power (the power difference was measured with my butt or seat of the pants). I have not used it on my TT as I am not sure if it is safe to use on turbocharged engines. The product does not stick to the block immediately so some of it might make its way to the turbos. If you have any NA go for it. The worst that it can happen is to lose a few bucks. You will the biggest gains on high mileage vehicles. I used one bottle every other oil change.