In my case, I wanted to change cars, set myself a limit of 6.5K and began looking on Autotrader, Ebay for what I could get for my money, didn't care at the start what I wanted just something different from my BM ci, narrowed it down to a Zed or Bosxter, drove a few of each and was on my way to London having seen a Boxster 3.2S spent the next 4 hours trying to get through London to see it, lost my rag, turned round and drove back home, that night I spotted a Zed and the following day was the proud owner of Roxy, not looked back since.
My view is is you really want a certain type of car, just go and get it. If you are worrying about running costs, servicing and the like go buy something more mainstream with a smaller engine and boring looks but if you really really want a Zed, then go for it cos you wouldn't be worrying about sod all else except getting the car you really want.