the shifter has to be installed from underneath.

get under the car and head towards the middle. look at the shift linkage that is "C" shaped near the end, and that is attached to the bottom of your shifter. remove that bolts and nut. you may also have to remove the other shift linkage there (I cant' remember). just remove the bolts from the bottom there and pull the old shifter out, and put in your new shifter. it's really easy. you may be down there for a while depending on how everything goes. def get under using jack stands. also you should buy shifter bushings for the shift linkage. it really does help, and is probably gonna be more beneficial than your short throw. i'm personally not a fan of the short throws, and i would recommend you keep your stock shift stem, and get new shifter bushings, you'll have more $$$ left ove than.