Thats a lot to do for just gas mileage. Let me tell you what I do.
Every day on my way to work I hit at least 100 kmp on the on ramp, Im usally passing people in the slow lane before getting to the high way.
I shift at about 4 1/5 to five thousand rpms.
I have a cold air intake, pacesetter exh head, a 3.5L throttle body and its chipped.
To save weight I have a set of fiberglass fenders, took off the a/c, no tar sheets, no spare of jack and I have a hood on order. (On order not going to buy, just waiting for it to come in.)
It has around 220 horses and I still get on average 35 in street and 42 in highway.