Wait. Are you saying you can't sell your CD MBP for only the difference in cost between the refurbished C2D model and one of those FW800 cards? I think you can and you are much better off with the all new ventilation system in the C2D MBP if you can swing it. Now would be a much better time to try this move than later after Santa Rosa is inside.
I think that even if the difference is a few hundred dollars more than the card costs, it would be way worth it to lose the CD MBP ASAP for that better vent system. 🙂