Find a boat that best fits your needs and budget, then modify it over time as you see fit. Price, length, displacement, draft, sailing performance, sail and gear inventories, etc would be much higher priorities as I tried to eliminate prospective candidates.
You're absolutely right. I've found the boats that meet my needs in terms of price, length, displacement, draft, sailing performance, etc. I'm now down to several different boats of the same two makes (CS36T or Niagara 35 Mk 1), some with heaters, some without.
For anything else, such as electronics, I would say the same - do my own modifications - but this is a matter of modifications already having been made - with big holes in the deckroof - and the possibility of making new holes or filling the existing holes.