Nissan recommends keeping rpm's under 4000 for the first 1200 miles. I've heard if you baby a new car it'll always be slow. I'd appreciate any comments on this subject ...

 

This has been debated over and over. Some baby it and some drove it hard. I followed the recommended breakin procedures.

Weird thing is when I went to get an oil change after the break in period and the nissan tech told me there's no longer a break in period. He said the engine is broken in at the factory.

 

Yes the ECU does adapt to your driving, but changing your driving style will retrain the ECU. Resetting the ECU should also help speed that up too.