If you need parts, as Welshy already said, both chassis are still available at Fiber-Lyte.
Standard Zx (and Zx-r MK I)
http://www.fibre-lyte.co.uk/fl/cars/kyosho/zx.html
http://www.fibre-lyte.co.uk/fl/cars/kyosho/kylaz1.html
Zx-r MKII and Zx-rr
http://www.fibre-lyte.co.uk/fl/cars/kyosho/kylaz2.html
The wishbones are the same in all the Lazer Zx series car (including the Lazer Zx-s).
Bye
Ema