Knighton,
As a new GT owner/driver, I can comment on my experiences so far.
Traction control/launch control-
I'm running a 351 CI engine with 400+ flywheel HP and torque, aluminum flywheel. 335/35/17 rear tires. No traction or launch contols at all. I have yet for the car to spin it tires on dry road from 2nd gear WOT on up. I have to admit that I haven't gone wild with 1st gear. No need to driving on the street, plus the tires are too expensive to burn off it. Wet road? I've avoided taking the car out in the wet. Even so, after owning a high HP motorcycle, you learn not to get over entheaustic in the wet with the throttle because they WILL spin the tires.
door locks -
I have locks on my doors, but to be honest, they would only deter people that didn't want to steal the car anyway. Realistically, all a person needs is a screwdriver to remove one of the side windows. A hidden transponder like Lo Jack or similar will end up on my car at some point.
dead pedal -
The car came with one, but I removed it because it was too close to the clutch pedal. Not much room between the fender well and the clutch pedal. It bothered me when using the clutch more than it was a help.
rearview mirrors-
Anything you can do would be a help. I put small outside mirrors on my car and can see....not much. To make matters worse, the state inspection station put the yearly sticker on the windshield right in the view of the LH mirror. OOPS.
cruise control-
would be OK for interstate driving. I haven't found the car to be that difficult to maintain at a constant speed. I've never had luck with any aftermarket systems due to high HP and touchy throttles. Wayne Presley advertises one with a gain adjustment that should solve this.
removable steering wheel-
I use a Sweet quick disconnect. I must say, at least for us tall guys, that it was well spent money to put it in the car. It makes getting in and out MUCH easier.
luggage boxes-
In my car, you can put a little in the door pockets, at the passengers feet(wife!), or in the front where a spare tire would normally go (don't have one due to pin drive and such a size difference between front and rear). What you could put in any of these places, I wouldn't call luggage! The only other area you could possibly put something is to locate a couple small boxes on either side of the transaxle/exhaust. These have been refered to on the forum before.
One requesite I had was to keep the dash layout as original as possible, but update the car with some new technology. EFI can be incorporated and mostly hidden. One thing I added was a small switch box on the steering wheel that does LH and RH turn signals, light dimming, and horn. All the toggle switches remain as original and functional, on the dash. Doing a lot of street driving, I would find the dash only switches to be cumbersome and user unfriendly.
I also added intermittent wiper controls. Again, mostly hidden except for a single black knob on the dash.
AC is a must.
Hope this helps!
Dave