Castle Blower on Dewalt Motor in Summit?

[fastbaja5b]

Hey guys, went the Dewalt 14.4V route for my Summit, and geared 18/68 after a 30 minute bash I was getting temps of 70-75C on the motor (granted the motor had an outwears on it.) That's a bit high for my taste, so have since gone down to a 16t, pulled the Outerwears and put on a CC Blower (being the only fan that actually fit the Dewalt's huge can.

BUT

Am I going to retain more heat through the Plastic Shroud, than I will move with the Fan? ie, do the costs outweigh the benefits of this set up?

Any ideas?