don't assume that just because you shift at a low RPM your gonna get better milage, i realize the 05+ has much more power than mine, IMO your better off shifting a little higher in the revs if you want speed and then upshift, rather than shifting at around 2000rpm and then mashing the gas and not moving\have the engine struggle, i usually shift around 2500-3000rpm depending on traffic and i shift into overdrive ASAP