mods are two brothers full exhaust, a complete K n N Air intake kit with lid of the air box, an fmf jet kit installed with a main jet fitted for a 0-3000 ft above sea level and a CDI rev box that lets me rev about 1000 rpms more then stock so my question is this what number octane would be the best for it i usually get the cheapest one which is the 87 grade, i usually like to drag race up a sand dune any suggestions and why it would be a big help thanks...