s13drifter, go to the nsw rta website and search for a pdf document about light vehicle modifications it outlines the formulas and everyting about what maximum size engines u can have in different weight cars. in any od the 1200 models the only rotar u can get engineered is a 10a the formula says the max disp. u can have is 2.1litres unturbocharged. because the formula works off the stock weigh of the sedan body version of a 1200.