Well, all these things still have been done. In this case with a Kleemann compressor. But Don't ask for the price tag.

And - if you want to build a compressor on a 3.7 stock engine, you'll first have to completely rebuild it.
Motor Umbau auf 3,8 Ltr - Umbauten, Modifikationen ... - Chrysler-Crossfire-Forum - Das Forum für Crossfirefans
If you have a AT tranny, it's much cheaper to do a 4.3, or 5.0 V8 conversion.
This one is a 5.5 V8 AMG conversion:
http://www.chrysler-crossfire-forum....otortausch-v8/
This is a 5.0 V8 MT conversion:
http://www.chrysler-crossfire-forum....chaltgetriebe/
Regards
Markus