I too have a 147 2.0 (selespeed)
The no.1 thing to watch out for:
- cam belt (and accesories) change interval is much shorter that the one in the manual. It is actually recommended to change it every 2 years, even if you don't travel many miles. If you don't know when the previous owner did this, you should do it to be on the safe side.
- engine-related parts I have changed in over 3-years ownership: thermostat (if there are any traces of leaks around its pipes it usually means it's worn out); air flow meter (it caused a check engine light warning); engine RPM sensor (it caused the engine to not start sometimes, usually when warm); - crankshaft seal which caused oil leaks.
- also, if the battery is old, you should change it. (A lot of weird electical problems maybe caused just by an old battery);
Also, 'normal' wear and tear items: front brake discs, pads, wheel bearings and suspension bushes (because of the hard suspension every bump takes its toll); rear pads; clutch kit; the exhaust rear box.
If you got a selespeed, this list will be double. (I assume you have a manual?)
Anyway, take care of it, or else it will disappoint you when you least expect it.