the m112 has to have alot to make it function properly.
You can get a low mileage one for roughly $400.00
you can get one with a pulley on it for roughly $350.00
you can get a ported one (depending on the port job) for roughly $500.00
to make it function you need "C" heads (off 1999+ 4vs) the lower intake manifold off a 2003/2004 cobra (sold mine for $400+ used) the top mount intercooler (OEM ones go for $250-350.00) and the front mount heat exchanger (OEM ones go for about $150.00) and the coolant expansion tank for the intercooler (sold my OEM for $30.00 aftermarket ones go for about $100.00)
you will also need the throttle body, plenum, and throttle cable from a 2003/2004 cobra. (about $100.00)
the M112 has different bolt patterns than the smaller ones used on thunder birds. They also have different bolt patterns than the ones used on lightnings. so be sure you know which one your trading for.
this is the best information i can give you. there are many other people on the forum who could give you better/more accurate/more detailed information.