All my other cars have factory key fobs, and I had a alarm/fob setup on my 82 that I installed, but it was so long ago, I can't even remember who made that unit. (Crimestopper IIRC.)
Worked fine, locked and unlocked the doors, and that's really all I wanted it to do. (Also had the ignition lock out, and a few other gizmo's that all worked, but I never really needed since the car was never stolen.)
The MK3 does not have an electronic hatch release, so putting that option into it would be a PITA right?
Just getting doors would be nice, and some alarm/lock out ability for the fuel pump or ignition would also be good. (No pump, no fuel, who cares if they can crank it over.... LOL)
On thing I did on my last one was put the siren inside the car, under the dash. (Not easy to get at, but damn loud when it's going off inside there.) I figured most people pretty much ignore the alarms anyway, so I was trying to agrivate the would be thief with a loud working environment. Also this tended to mute the "chirp" "chirp-chirp" when locking and unlocking the car so I did not attract attention to it.
In my job, I used to see theft claims all the time. Also have worked with the SIU (Investigators at our company) guys on a few serious cases in the past. (Theft rings, dirty shops, stuff like that.)
#1 Way to get your ride stolen is to have a loud stereo in places where others can listen in. (Like the parking lot of a mall, or movie theater...) Goes like this. Boom... Boommm, your bass is really kicking... Or just loud anything in a public place where your about to park your car.... Or even on your daily ride home, a savy thief will just follow you home, see where you park your car, and if you have an alarm with the fancy shit on it, they even now know what system you have when you lock your doors, and it says "System Armed" or whatever.
They get to work that night, and you come out to a screwed up car if they don't out and out steal the ride. (At minimum, your stereo is gone, window broken, dash raped etc.)
Knowing this, the perfect alarm would have a very small, two button remote key fob. Lock and unlock is all I need. Loud alarm inside the car. Activate superbright LED/Xenon strobe lights also inside the car, under the dash, or near the radio. IT would be very difficult to work with birght light in your eyes, and a loud siren in your ears. Ear plugs might help, but the light deal would make it that much harder to focus and steal your stuff. (And time is everything for the thief.) Only need one relay to cut either the power to the TCCS, fuel pump, or some other vital system like the coils. (Engine will not run without this hooked up, no matter what.) Keep in mind most alarm installers only hit the ignition wires, so if you know what your doing, you can bypass that pretty quickly, and everything else works. If you take out a system they don't know well, like the fuel pump, ignition or some other vital system, they will not know where you defeated it, and the car will be left as a result.
Just my .02, but what system has the nicest two button key fob? LOL That's the one I'd buy.