1. As far as I know it is the same suspension set-up in the rear.
2. Reading the owner manual it can only be turned off temporarily (ex for maintenance or to push the car by hand) and would restore at the next engine on cycle. (ref 1 below)
That being said, what is your concern with the automatic parking brake ? If it is the fact that you would rather not have to press the button to release it overtime you don't need to. The mazda 3 also has an automatic parking brake release. If you put the car in drive or reverse and press the accelerator, the parking brake will disengage. (ref 2 below)
Thanks for all replies, you put a lot of effort in that, but the parking brake remains the most annoying thing I have ever experienced on my car. Maybe it's because of the switch that doesn't take the command every time, maybe it's because the system doesn't take it and maybe it's because you simply can't turn it off immediately after seating yourself in. I don't care. It doesn't work right. I hate it. It pisses me off. I want it gone. Long time ago one person here smartly commented that instead of playing with the switch you just press the gas pedal to the floor and the car takes care of the brake by itself. So I am doing that more often than not.
This is a flaw and once I heard about the Turbo version - my first though was - did they fix the f*ing parking brake? not about Turbo, not about the 250 ponies, not about how much it costs, but "did they fix the f*ing parking brake?"
So to cut it all short - I will probably take a look at the car, I will probably take it out for a spin, but that parking brak will probably stop me from buying it. I am already looking at a Lexus replacement so chances are I will get that.
The torsion suspension is annoying, because roads are not straight and in some spots the car just wanders left to right back and forth and you can't do much about it - as the rear is not adjustable and the alignment can't fix that. I learned that it helps to pump it up to 37 PSI and it's better at that pressure, but it doesn't have a feel of a car that want's to keep the road straight at fast speed.
This forces me to be really focused and I can't take off a hand off the steering for even a fraction of a second. It makes the car impractical and not fit for longer trips. The dealer of course says it's perfect and there is nothing to worry about - so fine. I am not worried. I will not buy another one like that.
So these are the flaws. That torsion suspension is not that terrible as the parking brake, but nevertheless it's a flaw. Both of these flaws are making me search for a replacement.
I could live with the torsion suspension because I only commute to work back an forth and the commute is short - but if I had to do longer trips - I would not take the Mazda3 - but rather the CX-5 that is more stable.