Yes, the 112 is a better option for your 04 than the m90. It will bolt on with the assistance of an adapter plate. The last time I looked just the plate it self cost 900.00. Its not cheap to supercharge our motors.
You will go back on horsepower from doing this swap but the supercoupe engine made something like 315 ft lbs of tq which is a lot more than the 99 - 04 3.8's made at 225. So it has its pros and cons if you do this, it's your decision.
you would have to buy everything from the heads upwards. Including the wiring harness and computer.
It had 210hp, and 315 lbs of tq. Not a big increase over the split port 3.8(except for torque). maybe if you also stroked the engine to 4.2, might make around 260hp(i'm guessing,might be less-might be more)