It’s the word I probably hate more than any other when searching for a new bass……. “Upgraded”. The seller “upgraded” the tuners, pickups, bridge or whatever….. it’s a massive turn off to me, and usually turns me away from the sale. I want the bass to be as original as possible, so that I can decide wether or not the bass needs any customisation to suit me, not the previous owner.
Always keep the original parts, and put them back on when selling (imo). “Upgrades” hardly ever equal higher value instrument from the original stock bass, and you can re-sell those “better” (subjective) parts separately, and possibly for better gain.
Just my opinion, but I do like to see unaltered instruments (where possible) when I’m buying.