I also drive a black G35, though mine is a 2006 sedan but I wouldn't expect the paint to be all that different.
The clear coat is EXTREMELY soft, which means, that it is going to be very difficult to keep this thing swirl free. You are going to have to invest in some top notch wash products such as mitts and grit guards.
Working by hand, you're best option is to hide the swirls. I don't know much about the Megs 3-step system but I assume it is similar to Mother's. In the Mother's system there is a sealer/glaze (which actually has NO sealing properties, its strictly a glaze!), that will fill in scratches. Just make sure the Megs system has something similar.
Also, I would stay away from whatever wax they suggest as step 3 and use Megs NXT instead. It is VERY easy to use, fills defects well, and looks pretty darn good.