I can`t comment on the 180 as i currently drive a Mk2 110 model which is a cracking drive, its a proper little rev rat & goes really well!
On the ZR160 front i used to own one of these, mine was a early mk1 on a Y plate & have to say they are so underestimated & go like stink, however the build quality is`nt the best on them but if you can live with that then you`ve got yourself a nice little pocket rocket!
If i`m honest though the ZS is the better car to drive out of the two, the ZR is like a little go kart, whilst the ZS is more touring car & handles like its on rails!