RE: Upgrade CP or get a T-Rex?
I made the mistake of thinking the CP would be an inexpensive companion to my T-Rex. After spending a ton on the CP to try to get it to be half as good as the T-Rex. I finally sold it all on ebay at a huge loss. T-Rex is the best bang for the buck I think.
(Actually mine was an AXE CP, but the same story holds).