I seriously doubt you'd see much, if any, improvement. There are a number of other things you'd have to rework, port and polish, or flat out replace with something different.
These include:
Port & polish "Y" pipe (or possibly replace with a larger custom Y pipe and rework the intake surge tank to accept it)
P&p the upper and lower intake runners
Dump the stock AFM and go with either a 3.5" GM MAF or go MAP
Replace all the intake piping up to the TB with 90mm pipe
There's one member on here who's running dual mustang TB's on his N/A... can't remember who though. Look for it in a recent thread about intakes in the N/A section... he may be able to off up some more advise.
Oh, and YES, it's going to take a fair amount of work. Depending on what it's from adapting the TPS may not be a huge issue, just a matter of whether the mounts can be made to work.