(1) do you feel the components on the more well known kit brands they sell match up in quality with the factory cars ie Superformance Backdraft etc?
I'd look into what components are set up on the cobra kits your thinking of buying. Mine has a Mustang 2 front end setup and was easy to upgrade to coilovers etc. The mustang 2 upgrades are quite ubundant. Plus think about how you are going to use your cobra.. What rear gears are on it, will help to determine the rpms it will be running at in 5th or 4th gear on the freeway.. Is it going to be tracked or just a street cruiser.
Find out what year the parts are, and what it's compatible with. For example do they take mustang brakes or lincoln and what years..If it has donor parts what application (year/type of vehicle) did it come off of. Having the replica/kit built from a company/manufacturer that you can contact helps with getting part numbers.
(2) traditional Carb set up vrs fuel injection pros and cons or just preference
Fuel injection is great no doubt. I have a Carb 351 windsor which has many upgrades/replacement parts available. The one advice If you decide to go carb is to get it on a Dyno..Not for horse power but to get it tuned. Tuning is critical to ensure proper timing and jet settings. You don't ever want to run a carb engine lean. Plus the best thing I did for my carb was to have a manual choke installed. It starts on the first turn of the key..every time. Upgrading or changing out the fuel pump is good too. For me it was good to know it was new and wasn't going to fail on me.
My engine has been very reliable. I drove it into work 2 to 3 days a week last summer and fall. Went on many long weekend cruises no issues...The cobra is so light gas consumption never felt outragious. I even romped on the gas plenty...
I had mine dynoed, unbelievable the difference after it was dynoed. Pretty affordable to have dynoed. It cost me under 200 bucks. Personaly I like the carb setup. I like the sound and the convienience of fixing minor things myself. I too am not much of a mechanic. Good at swapping things out and torqing bolts.
(3) live straight axle vrs 4 wheel independent
I'm running on a ford 9 inch rear axle with rear slip. The difference was changing out the Coil springs and shocks on the rear. It rides great..quite nice for street use...
I'm no expert just some personal experiences. Drop me a line if you have any other questions.