They not rare, they just expensive as fuck, as they "classics".

UK models are worth an absolutle fortune as the Irish worship them like they were their gods, but can get a half decent Jap import for about 4-5k, which is a hell of a lot of cash for a mid 80s 125bhp 1.6litre car, but like said, "classic"

Finding one is piece of piss, aside from id guess a good 10 or so for sale in the UK at mo, there about 15 on Irish autotrader at mo, and I can get a list of literally hundreds of them for sale in Japan, the proper FOB price for them too, ie paid for in Japan, shipping etc paid for, you just collect from the docks and pay import taxes.

Most are modified, infact you will be lucky to find a 100% standard one, though why youd want that is beyond me.
Most come with exhaust, filter, coilovers, diff, etc, not mega modded, but can easy enough find a complete weapon too.