Saying financially bad idea, if you enjoy doing that fine, but check out the listings, the really nice decked out airplanes have more in them then they can get out of them, by a long shot. Then you get the other end, they buy cheap needing everything,. no good either!
ownership of airplanes is not cheap, but if you use your head you can cut in down by half or more. Just read first annual $17,000 on a maybe $50,000 airplane. Not a good deal.
That is why a pre sale is so important, offer x amount of dollars contingent on an acceptable pre sale inspection (you pay for that). worth every penny!
just look at a nice stack of radios and call an avionics shop, see how much to install the same radios, it will shock you.
or just aileron pushrods 8 inches long on my 210 $700 each 10 years ago, fuel pump $1,500 10 years ago. it adds up quick!