^ they ONLY do cause if you run a DOHC ka then they put you in the class with turbo FC and other faster cars....Stock turbo FC's make 205hp STOCK they alow some engine bolt ons like intake eahcust manifold and exhaust along with rebiabilty parts....getting a DOHC to 205hp in n/a form is hard and is against the rules for that class, its stupid i know, i guess there just scared of the DOHC ka's power lmao. ither way the SOHC S13s hand the non turbo FC's and other cars there *** on the track reguardless.