Well----I've not made any SERIOUS changes, although I am using larger dia. wheels (3")---Also 1/4" length of large fuel tubing under each canopy screw hd. (allowing it to compress & act as a lock), they can & WILL vibrate loose!---I just happen to like "Sullivan" tailwheel assy. & so thats what it has---Thats about it, all the other hardware (except wheels) seems to be good, IMHO, maybe the "Best bargain in the store" for the money----OH! & the control surfaces are VERY sensitive!!---Especially the elev.---It's HUGE for the size of the airplane!!---Now about SERIOUS changes---I am considering cutting the elev. counter/balances off & attaching them permanently to the stab & possibly shorting & doing the same to the ailerons (4" or 5")---(I'm sure you can tell, I'm NOT a 3D flier)---Hope this helps---