Most of mine are somewhere in the lists already provided, so I'll just add
Screwless spinner
DJM Throttle quadrant instead of Cessna-style push-pull knobs
Andair fuel pump allowed me to cut the height down on the cover, and I mounted the fire extinguisher there with a really nice racing-style quick-release mount
That one allowed me have Classic Aero make a nice cover for the flap bracket mount, to match the interior
Local auto upholstery shop fabbed up similar covers for the portion of the canopy where the rivets are visible on the interior, with material from Classic Aero to match interior
Removed canopy release handle (radio stack interfered, and we tried all sorts of unsatisfactory solutions, eventually decided screw it); and instead of bolts through the hinges, I used quick-release pip pins with an L-shaped handle. The canopy hasn't been off since it was painted 9 years ago
, anyway.
Wemac vents
Anodized rudder pedals, machined ball mounts for tip-up struts, canopy latch, canopy exterior lift point
Upper tip-up canopy lock cover to hide the mechanism
LED strip under the panel cover portion of the canopy (dimmable)
Rudder cable clevis fairings
Hi-loks fasteners instead of screws for canopy to canopy rails (and Sikaflex all around)
See-through brake reservoir (forgot who made this, dunno if they're still around)
Split all 3 nylon blocks for the brake mounts...a real time- and frustration-saver
Cockpit footwell lighting installed up under the dash
Aveo position/navigation lights all around - zero radio noise from RFI! Also, ALL electrical grounds go back to the FOT, none use airframe grounding, so that may have helped there, too
AVEO Rockrack switches, but I don't think they make them anymore
Oil cooler shutter
Oil cooler shutter, Alternate air and Cabin heat locking push-pulls from McFarlane with laser-etched labelling (and color-coded blue, red and black, resp.)
Engraved fuel caps (no stick-on labels on the wings...in fact, *everything* on the plane is self-labelled...there are no labels on the panel itself...every button, knob, etc., has the function labelled on the item itself)
Main, Essential and Hot busses with ATO fuses behind the passenger side of the panel; no resettable-in-flight fuses or CBs (BUT...I did full FTAs and fault trees on the electrical system to ensure that no safety of flight conditions could be created by this design)
Keyswitch interlock for mags and starter (LOTS of debates about this on this forum...have fun!)
Hex rods for flap actuation rods to replace the standard cylindrical tubes (torque tube-to-flap rods)
That's all I can think of (that hasn't been mentioned elsewhere). Lots of fit and finish work, like epoxy w/ microballoons to fill and blend things like empennage tips, etc. (Tons of work on those, btw, but they look *great*). PM if you want details on any of them.