[jimbo2012]

Not an expert just my thoughts.

To move to garage, one full day two men + new duct work rerun elec and lines to compressor new freon, my guess $1,000-1500+

The air handler gets its air from the return duct or grill in usually the adjacent room not from the room it's located in.

So you can enclose and add sound proofing I believe, you will need access doors and perhaps certain switches may need to be relocated, but it is basic carpentry, one man one day plus materiel, my guess $200-250.