I'm never selling mine RKT,...I'm going to let it wear down to the housing before I'm finished with it, then it can become an ornament of some kind in dedication to those detecting gods that help out soo much,... I hope my great great great grandkids look at it in awe and think of how it helped me to build on the family fortune that they croon over soo much(ha),... so it would not matter to me if I rip into my machine and make a few changes(I would just have to up skill first).
Even if I end up with another machine, I would still hang onto this one as well, as the kids would probably use it if I had another for myself,.. plus as I know the machine so well it makes it easy for me to show the ropes to someone else with it. But then my machine was cheap enough and has paid for itself, so I wouldn't need to sell it to make an upgrade.