Every boat I've owned (and probably everyone else too!)! As soon as you buy them you got more in them than what they are worth!
In actuality, I could see me going that route with my boat. I really love the boat and it is the perfect size for my needs after going through 3 other performance boats. I'd like to do some changes such as external steering and then motors mods or replace them with more power. Either way, it would be a money losing proposition but if you like your boat and plan on keeping it for a long time I think it's worth making it the way you want it (to a degree).