Best Brushless upgrade for GWS Slow Stick ???

There are so many different options, and the specs are often 
incomplete. From my research it seems that the kv number 
that all of the brushless motors provide is an incomplete 
specification. From what I read what really counts is the 
Watts of power, and Watts per pound ranges from 50 to 250 
depending on the performance desired. Is there any way to 
convert the kv number into Watts?

What other things need to be considered?  (motor diameter, 
the shaft diameter, the shaft length, RPMs, torque, volts, 
amps draw)
I don't know what the final weight of my Slow Stick will be, 
I am guessing that it will be somewhere near a pound. It may 
go as high as two pounds with a heavy motor and battery. I 
am shooting for the best performance for the least cost, 
thus I am starting with NiMh batteries.

The best guess options chosen so far:
 
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5220&Product_Name=HXT_2030_(130S)_4300kv_Brushless_Inrunner

  http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXKKK7&P=X#partsusage

 
http://www.stevensaero.com/GWS-Outrunner-Brushless-Motor-2212-13T-GWBLM003A-p-18330.html

 
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=4178&Product_Name=GWS_BL_Inrunner_Motor_3900kv