Hi Bob Z.,
Start quoting, we're all interested! 
Jerry
OK, Jerry - here are a few:
My Icarus Jr - no canopy on the plans but I put one on. That's a cosmetic change. Also, I put on a fixed gear because a drop-off was shown on the plans. It's never been protested and has finished first a number of times.
A fellow flew a Nobler with wheel pants in classic at Huntersville. That's a pretty dramatic cosmetic change.
My Viking has an I-beam wing and 2 inches more span. Also, I shortened the nose by one inch to avoid adding tailweight. Many first place trophies, never protested, not even at VSC.
A fellow flew a Sterling Mustang at the Circle Burners event. Dihedral wing and wing-mounted gear. First place, zero protests.
A Nobler showed up at Brodaks with a beautifully done Argus type cowl. Cosmetic change, zero protests. I do not know how it placed.
A barnstormer flew in OTS at Circle Burners. It had solid flaps instead of built-up. Also had a bubble canopy instead of the original sewn version. Cosmetic changes, no protests. It won first in Advance OTS.
The original Stunt Rocket has a drop-off gear. Mine is fixed.
Probably a lot more but I can't think of any at the moment.
Bob Z.