One of the bigger shifts in FE was a relatively simple one, installing paddle mirrors instead of the big 3 point towing mirrors. This one change meant the difference of only 5% improvement in FE, but it also meant that I could keep up and stay in the draft with other vehicles. Before that change I'd have to go close to full throttle any time someone ahead of me stepped on the gas or we started going up a hill. A lot of times I'd just have to wait for someone to pass me before I could catch up into the draft again.
I have a Dodge Neon mirror that I'm going to hack up and install on the driver's side. The stock paddle mirrors are so tall because they don't tilt vertically, so half of the height is totally useless. I know this will probably be a small change in FE, but it should only take a couple of days of fiberglass work to make a new mirror housing.
