Spray painting the radiator shrouds black. They shoulda come that way in the first place.
Home-made fender eliminator.
Bar-end mirrors (Napoleons at ~$30 a pop, not cheap, but not expensive)
Sargent Seat. Not cheap at all, but your boys will thank you.
Best Stealth Mod No One Will Notice But You?
TORS. Looks stock. Runs stronger. Buy 'em used and save.
Most utterly unnecessary mod offering only modest practical improvement while remaining totally, completely bitchin' to the point where it gets the most comments?
Pazzos. Go figure