Not sure which direction the thread exactly took, but I'm gonna give my 2c haha
Personally I aim for around 60% of the new price whenever I buy or sell. Depending on how good the condition is etc...
Everything you did to the Instrument/Gear can be considered decreasing the value, not increasing it in my mind.
Because why should I have to pay for additions you decided to get, who's to say I was ok with those choices?
For example pickups: If you still have the original ones swap them out with the add on, but don't expect me to pay more for pickups I don't want.
And it's the same thing with profiles on the Kemper. It's a nice bonus, but you can't expect people to pay for something they didn't intend on buying themselves.
You'd have to be lucky to find someone who exactly wants what you did to the thing you sell, or your collection of profiles fits the taste of the buyer.
Which wouldn't be a good scenario, cause most non-Kemper folks wouldn't know what kind of profiles they want I guess.
And if people already had a Kemper but sold it, then I bit they kept the profiles in case they get another Kemper at some spot.
Either way, the profiles/upgrades are non essential for a 2nd hand buyer in my mind. Nice bonus, but don't expect to get payed extra for it.
Example: I wouldn't pay extra for a guitar that had it's pickups switched for EMGs. Why? Cause I still have a couple laying around at home.
As far as the mentality goes for sellers: I can't speak for all of us vendors, but I think most guys just don't want you to zip up all your profiles and sell them yourself.
If you leave them on your Kemper then I also don't care too much. That's not doing any real damage in my mind, compared to pirating/sharing groups at least.