Because my friend just told me about it when he saw the ads about new GM trucks got Quadrasteer...Which is just an out of date technology.

wuite possible.. my friends old 88 prelude has 4 wheel steering

so does the skyline gtr

But which year did it have it?

YES, I am 90% the 929 has 4WS, as does the MX6 of about 1992.

the newer shape, from 92 to 94 they definately have 4 wheel steering. Im not sure about the 95 model and onwards.

The Mazda 4WS system was optional on Sentias/929's. I've got a late model Sentia Exclusive 4WS (imported from Japan) and now I'm used to it, it is a nice drive. Turns inside 5.0 meters.... which is amazing for such a large car.
The 929 finished in all markets other than Japanese Domestic in 1995. In Japan, they had a new Sentia in October 1995 which finished in 2002. There were 5 variants available, 2 of which had optional 4WS (Exclusive & Royal Classic).