welcome!
now, let me tell you as well not to switch to the auto.
your cars main PCM is in communication with the transmission computer. Your car did not come with the computer for the auto. your main engine and body wiring harness does not have provision for that either.
your abs as well may have a tie in to these systems.
On an older car it may be possible(tho still very hard, what with pedals, shifter, cooler lines, mounts, axles, possible steering rack bracketry, possible suspension brackets/fittings), but on anything newer than about 95-96, the OBD2 system includes many feedback items for transmissions too. At best your car will always have a check engine light. This will make it so you cannot go thru aircare. Ever.
you will also possibly have shifting issues, engine driveability issues and other things.
The other thing you HAVE to keep in mind is that the differential in the transmission(actually 2 of them, one front and one center) are most likely different than in the 5spd. All 3 diffs have to be a matched set(you have a rear one too) or you will QUICKLY ruin the center diff and your car will drive at best, wierdly and most likely sieze up on you while driving down the road. If it locks up while at hiway speed, you can end up in the ditch or in the path of an oncoming Peterbuilt. Its happened. There is a recall on both sides of the border for a seal that causes a leak and a locked up center diff for this very reason.
