I have a bit over 310K miles on my car (500 000km+). 260 000 miles of which I put on myself, in the last 11+ years.
Is the car reliable? Compared to what? Something like a 300zx twin turbo? Yes. Dodge Stealth? Yes. Mitsubishi Eclipse/Talon? Yes.
A 1998 Civic? HELL NO.
These are bloody old and COMPLICATED cars, and even with the best of maintenance stuff will break, wear out, corrode, crack from the heat etc. etc. The simpler and less powerful the car, the better chances it has of holding together.
Anyway. Off the top of my head, things that went wrong with the MKIII in the past (keep in mind, my mileage and how long I've had this thing):
1) It's on it's second engine. First one got rod knock when I ran it out of oil while being stupid and driving the piss out of it. Junkyard engine in there now (for about the last 200K).
2) Body rusted to hell and back (rust-belt car).
3) CPS and AFM crapp out.
4) Oil leaked out of:
-valve covers
-front main seal
-camshaft seals
-oil pan
-transmission
-LSD
-Power steering rack.
5) Brake caliper pins seize on a constant basis (no matter how I rebuild them or what I do).
6) Electrical stuff breaks:
-Power window switches oxidize internally
-Interior heater/AC fan wears out
-All the wiring and connectors/sensors under the hood get brittle are cracked and overheated and fail randomly.
-alternators fail
-batteries fail
7) Original coolant hoses basically all blew one by one, untill they get all replaced. Radiators clog. Fan clutches blow up.
8) Suspension ball joint, pivot bushing, insulators etc, all wear out and your car will handle like utter garbage unless fixed.
9) Clutch wears out (master cylinders, slave, friction plates, bearings).
10) Turbos blow up.
Hell, I'm sure I've only touched on 40% of the stuff.
Don't mean to scare you, but if you don't have a good supply of money, and enjoy working on these cars as a hobby, look elsewhere. It's silly to drive a 3600+ lb, seventeen year old car as a daily driver, unless you love the car for what it is (and what it can be with lots of work).
Oh yeah, let's not even mention gas mileage with the fuel prices these days. :icon_conf