I completely understand!! Do the "crazy" just to see if you can do it!!
So, if you don't yet have a ScanGauge - (oh wait, I just saw you have a pre-'96 car & plan to get the MPGuino) - get it soon. Testing your mods one at a time is MUCH easier, faster, and cheaper with one of those devices than trying to do it "fill-up to fill-up".
Read MetroMPG's "correct way to do A-B-A testing" thread and use that technique to figure out what's happening with everything you try. The good thing about wanting to do higher speeds is the aerodynamic differences will show up better that way. Aero mods won't be as pronounced at 50 as they will at 70.
I'm anxious to see how you make out.
