205/40/17 is pretty small for the rear. I ran that size up front before but not rear...
according to this tire size calc:
Tire Size Calculator - tire & wheel plus sizing
your speedo is about 3.2% too fast... that's not
that bad, but it is probably contributing to what you're feeling with the RPM.
I ran 225/45/17s on 17x7 for a while and loved em..