Originally Posted by vm

As previously said the TopTier gas is the BMW approved and it mainly indicates that these gasolines has twice the amount of detergent specified by the American Petroleum Institute (API) standard. The only point is that Shell (according to their website) has 5 times the amount of required detergent IN THE V-POWER ONLY. All the other manufacturers and Shell's lower octane formulations have the required 2X amount to comply with the TopTier standard, which is probably more than enough.