Yes you will need a new ECU. Also, the ignition swich is weird on them (security issue), i belive you need to take the ignition switch out of where ever you get the ecu from (could also be the engine)
I do not no alot about the 7th gen except a little about the SI so if I say something completely wrong, correct me. D and b series engines have the tranny on the passenger side of the car where as the K series (rsx, element, crv and SI engine) have the tranny on the right side. This means that they spin oppisite then the b and D. If someone put a k into a d series chassis, most likely they would have an engine with 5 gears of reverse and one really quick 1st gear. Unless they TOTALLY changed the d series for the 7th gen, you can still put a b series engine in there.