Don't go with the K24z2 its shy a few HP compared to the K24a2 and k20a2. You have to decide whether you want to go boost or all motor for your tranny choice. For all motor get the RSX-S tranny, for boost people like to use the 5-speed ep3 tranny because of its longer gears works better with boost. You have 2 options on the ecu, Hondata flash pro, and Kpro. If your serious about building and boosting your motor you will need the Kpro.