Originally posted by InitialD
Looks like from the setup sheets of the Kyosho drivers at the WC, the Sirio engines used was a S12 TRP-I. That's a 3 port ABC engine. Not AAC. Wonder why AAC was not used if it is more superior in power... 
Found out that it was because the new S12 Evo 2 TRP-I (IFMAR) World Cup Edition has a new piston/liner set Part Nš S12041223 ABC IFMAR with new timing, which has first been produced in ABC configuration, and has not been produced in AAC yet on the Sirio line of engines, but you can get them on the Collari line of engines.
AFM