royal purple 5w30 is about 45 a gallon. its a bit more than others, but you can tell the difference immediatly, the car seems happier if that makes sense. put it this way, Cruise use RP in all of their cars... its in qrt bottles aswell, so you get one to leave in the car for topupz. and yeah, the sard plug is about 7 quid, and i highly recommend them.