1) Are the gearboxes exactly the same, i.e. ratio's and gear set strength-Yes-gear ratios different
2) Are the drive shafts the same strength-no but close
3) Although the diff ratios are different, are the diff strengths the same, yes
4) Does the 4wd ATTESA system act the same way in both cars, i.e. sampling rate, torque split etc-no
5) do the GTS4's have a 5 stud wheel pattern (I read somewhere that non-turbos have a 4 stud) 5 stud