Take a look through the center fold of trade-a-plane and you can get a
basic idea of overhaul cost on individual engines. Overhaul is the main
cost of engine care. Cost of engine overhaul for a give type of engine
will also give you some idea of cost of individual cylinder overhaul
since you'll probably need to pull a jug or two and maybe even do a top
overhaul before TBO. A lot of that depends on how you or the previous
owner have been running the engine, how good the last overhaul was, and
what type of cylinders were used.

Aside from that, you'll need to have some specific engine models in mind
to get an idea of quirks associated with that type of engine. Some
engine types are prone to going through cylinders at greater rates than
others, etc. Horse power and manufacturer don't have as much to do with
that as just the individual model of engine.

You might want to put some queries about specific engines out on this
newsgroup and get some feed back from owners of those. When you get
narrowed down to a speciic plane manufacture - say Cessna - join the
type club and talk to those folks too.

Helen