First off, doing a right-hand conversion severely risks destroying the structural integrity of a car, so unless you are REALLY good at it, don't do it. Now on to your other questions:

As long as you use the wiring harness from your USDM car everything else driveline-wise will be plug-and-play. If you don't have the harness, buy one for the $150 you can get one on ebay. The amount of wiring involved when using the JDM harness isn't worth it and it takes even more work to get it to look factory. The other parts in the JDM clip that won't work in your car are the throttle cable, clutch lines, brake lines, and steering linkage. I'm probably missing some other things, but you get the idea.

$4500 for the CTR front clip isn't a bad deal when you consider what else you get with it. Front suspension, brakes, axles, headlights--the steering wheel and gauges alone are worth several hundred dollars here in the US. If you don't mind getting rid of the shell when you're done with it, that might be a pretty fun option for you. Good luck.