ZS is the only one I know thats had an unrealiabel one, I've had my one for nearly 3 years, great car, first derv I've owned and would buy another one.
Mk 2, 115 and all the body kit of the 180, only ?125 road tax a year, ins less as well.
Few tweaks and you can get 130 - 145 bhp plus plenty of torque.
Check if the belts have been done, if not knock the price down a bit.
Only trouble I've had is sticking rear caliper, that needed new disks and pads, should go well after 1500 revs when the turbo kicks in.
MAF sensor can give trouble but can be sorted easily, cant think of much else that gives trouble.
Best of luck with the search and hope you get a good one.