I have a freind with a 96 188 cobra dual console with a Merc 150 EFi. 5 inch jack plate. He has a 23 Mirage on it and gets a fairly good hole shot and a whopping 53 mph gps at 5400 rpms. And he reads about 12 psi. The shaft is 4" below the pad. All this with a 34 gal fuel tank and his light 275 lb butt in the seat. Any ideas what he should do to improve this boat?