Unless the mod adds function to the machine, like a color DMD, cliffy’s, airball protectors, quiet fan for stern power supplies, a controller that adds rules and new sounds, pinstadium lights, etc. don’t expect it to add any to the sale price of a machine. Things like mirror blades or art blades might add some but probably not. Powder coating and fresh paint will get you extra money on an older machine if it is done as a restoration. On a new Stern, it’s probably money down the drain.

Many people like adding figures, home made 3D printed toys, and other goofy stuff just because they like to bolt on crap in the name of ‘modding’ that don’t do anything for the sale price (so don’t pay extra if someone has done it already). I like Mezel mods stuff, but you will never see a cent of that money back on a sale with it in the machine. You would be better off removing it and selling it separately to try to get back any of your money spent.

I really like the stuff you make, especially your Krang mod. That's awesome.

All that said, I wouldn't say "pretty much anything" is recovered. If you go private party sale, you can ask anything you want, and wait on the right buyer who shares your tastes.

If you try and trade in to your local brick and mortar shop or distributor towards a new game, expect that any of your mods that aren't a shaker, color dmd, invisiglass, topper, etc. but purely aesthetic probably won't move the needle.

I don’t understand the Tron obsession (or the recent Quick Silver one for that matter). Neither game is all that good to warrant the prices and adoration. People will pay 15k for a beat up routed Tron that looks like it had a 100 plays with a cat turd for a ball, just to say they have one then try to flip it for 20K.