Dead simple to remove – the torx bit is all you need to remove them…not sure of torque to replace but when I replaced mine I made sure it was nice and tight – it didn't rattle or move before I removed mine, so I made sure it didn't rattle or move when I put it back in.
I think it was only the torx bolts at the front of the seat and then the whole thing lifted out.
Only issue you may have is with the seat not resting as it would be in a car i.e. base flat on the floor (I found it took up less space on it's side) then if you try to lift the back of the seat it might not work as the seatbelt lock system is in place – so the seatbelt won't extend and the back won't rise. Easy fix for that is to place the base of the seat on the floor (as if it was install in the car, then the back will rise up with ease).
I'm guessing you have the previous style car? If so, I think I managed to get almost 6" extra space in the car which meant my bike(s) could go in straight without any problems (with the seats in the other 2 would be sitting at an angle to fit in).
A 5 minute job to remove or reinstall.
