if its anything like the ae82s and 92s then you just take off the boot and knob, take off the center console (there's usually a couple screws scattered around the sides, etc.), then you'll see the shifter mechanism. I've only done it on a ae92, but I'm guessing your car will be pretty similar. On the shift mech. you'll see some bolts (possibly 4, 1 on each corner, with two cables). Undo the bolts (I think they were 12mm on the ae92, don't quote me on that though). They'll be pins holding cables to the shift lever, take those pins out and the cables will be free. Theres a clip holding each cable to the mechanism base, just pull those clips straight up, and slide the cables out, take off the whole mechaism, slide the new one it, reattach everything, and your done. I'm not sure what kind of short shift you have, is it just a lever? or is it a whole new mechanism like the TRD ones?