Apparently, Renntech (well known Mercedes Benz tuner) is making performance packages for the 2005 Chrysler Crossfires. If they are capable of tweaking the Crossfire ECU and installing camshafts and ported/polished heads, then you can be pretty sure they are capable of cracking open the 300c ECU and doing mods.
I'm at work right now. Anyone want to call and inquire? 561-845-7888
Looks like good news could be on the horizon for ECU modifications.