Its very simple to do. You do not need to get under the car. Its all done from the interior. I did it in just over an hour but thats because i started at dusk and it got dark damn quick. My friend had to hold a flashlight the whole time so i could see lol. If you're not dumb like me and do it in the daytime, it shouldn't take you more than 30 min with the right tools.
You can do it all from inside. It's no problem. Bout as easy as rotating tires.
Remove your shift knob. Pop the shifter boot bezel off by pulling up and out gently. You might want to disconnect the two lighter wires and completely remove the bezel for clearance. Remove the shift arm (2 bolts). Then remove the lower boot (4 bolts). Remove the shifter bolts (4). Now pry the shifter off. It's stuck on with black RTV. You might want to reattach the shift arm for levarage. Once off, clean the old RTV off the seal area. Lay down a clean bead of RTV (don't skimp, but don't be sloppy either). Install the new shifter. THe rest is the reverse of the tear down.
If you are real ambitious, and want to get under the car, now is an excellent time to drain and fill the tranny with lube. Just put the front of the car up on ramps of jack stands. Block the rear wheels. Remove the tranny drain plugs (2 I think). Let it drain. Replace the lower plug. Slowly fill the tranny back up by dumping tranny lube into the open shifter cavety until it starts draining back out of the top plug (then you are full). Replace the top plug and finish the shifter install.