The car seems really genuine and very well looked after from a fellow enthusiast. I was going to buy this but due to change of circumstances I bought a Panda 100 in the end.
Lowering is not always better, there are cases where a car rolls more when lowered due to the roll centre being wrong (been there and done it with factory option STi springs in a FSTi).
Also a suspension needs travel to work (unless you travel on smooth roads or on track).
On a different note...
I am also after one for the 182 as I was only pointed to the one below which I think is for the 172 only? Or are they common for both models?
https://www.dropbox.com/sh/eh8ke9p26msy3r6/eoI_Kaa2Em
When you say diff rebuild, what was wrong with it or did you just change the bearings?
The diff bearings should be reasonably priced (they were around £80 or so for my 205 GTi about 10 years ago).
Indeed about the Quaife, I had it in both my 205 GTis and it was one of the best modifications...