Welcome.
The 900ie is a great model. It comes with easily tunable open loop fuel injection and hot cams from the factory. If you are rebuilding the top end, hi comp pistons really wake these motors up. A light clutch and flywheel also help response. You shouldn't need a Powercommander and tune if you keep the airbox stock. If you open the airbox you will. Sponsor Monsterparts has Powercommander units. There are also ECU reflashes from sponsor Motowheels. JE pistons provide good bang for buck and the whole kit is cheaper than the oem ring kits.
Cheers.