some photography of interest:
above: naked blackfly belly. note the complete lack of OEM front tray of any kind. the control arms, exhaust, oil pan, stabilizer bar all dip down into the flow. now you see 'em ....
now you don't! cardboard prototype front undertray installed. mostly duct taped on, but some zip ties and a few screws were used (not visible). it's actually quite secure and firm.
note it overlaps the control arms. the closest attachment points are far enough ahead and behind the control arms, that the tray can move as they do.
i trimmed the tray to permit tire clearance in full-lock with about half an inch extra.
middle undertray in place. looking forward from the middle of the car. for testing, i plan to cut away the cardboard near the exhaust and tape aluminum foil in its place, leaving a few small openings.
the middle section is done as of tonite. another hour or so will have the rear undertray mocked up, then i just have to wait for a good opportunity to do some test runs, then yank it all off on the side of the road and re-do the runs naked for comparison.