Dont buy one for economy, i love my car but in all fairness its absolutely crap on fuel unless your grannying it down some nice straight roads. Most i have ever had out of mine is 44mpg and that was doing 100 miles down the M1 at 60mph. I average about 30mpg doing an 8 mile round trip to work 5 days a week in mine. Going out with the intent of having a huge amount of fun its sub 20's easily.
As already said you will have to push it to its limits to get the best performance from it, so if you a spirited driver you'll become a friend of the local fuel station.
Reliability wise they are very good with just a few small niggles letting them down. The first is the clutch cable as it wears out it gets heavier and this puts strain on the (second niggle) pedal box causing it to fracture and the whole lot to replace can cost in excess of £400 (i would know i've replaced both
)
Buy one with a FULL service history as parts can be expensive, especially brakes. The other reason for this is that these cars have to be driven hard to get the best from them, meaning poorly maintained cars will suffer from more serious problems such as head gaskets and gearbox issues.
Body-wise look out for rusting on the rear wheel arches, the lower sills and the rear tail gate, check the foglight lenses also as these are prone to getting stone damage. On poorly maintained cars the laquer can also peel especially on the bright flat colours such as tornado red and kiwi yellow. Also check for wear on the drivers seat bolster
Lots of things mentioned to look out for there, but don't let that put you off. Use them to avoid buying a dog or as bartering points to lower the price of the car. High milage isnt a
problem, so long as its been cared for. Mines done 115,000 miles now and goes just as well as it did on 50,000 miles. It all becomes worth it when i fly out of a left hander at full throttle in second gear and just go until i run out of road
