Hi, welcome to the club.
Watch the gearbox if it's a 1.5, the oil filler hole in those boxes is a bit low so there's not enough oil in the gearbox and it can wear out. I'd guess that if you jack-up the car the right way when filling it you can get round that but never tried it, someone else may have more info or search around the forums (you'll find more technical info if you're a member, though, well worth a few pence a week in many ways).
Timing chain can stretch. Expensive to fix.
Both problems are well known but don't seem to happen *that* often.
Front and rear break callipers can bind sometimes, worth keeping an eye on.
Not much else I can think of really other than those, keep an eye out for rust (particularly on the front crossmember, get that fixed and treated if you spot it) and that's about it.
IF you're thinking of modding it cone air filters don't seem to work as well as good replacement panel filters. The N16's handling is great but much better on good lowering springs (I'd recommend eibach pro) and incredible on coilovers (B&M). Not much off-the shelf modding stuff available, particularly for engines, but dig around the member's rides section for ideas and feel free to ask people stuff.