Which tennis racket should I use?

I want to buy one of the Babolat pure drive models and im not sure what is the difference between them and which one is better for me.
I'm not that strong so im looking for a racket that doesnt require a lot of power.
That is the main thing im looking for but also I need a racket that is good for a lot of spin.
I usually play in the baseline and im not much of a server. (I use two hand backhand if it's important).
The rackets that i heard of are: Babolat Pure Drive GT, Babolat Pure Drive Cortex Standart and Cortex Plus, Babolat Pure Drive Roddick Gt, Babolat Pure Drive Lite GT, Babolat pure drive Plus and the AeroPro Drive (Cortex). Some of them may be the same....
Thank you!

Get the Cortex plus, but theres two the Andy Roddick one is for surves and is better for a two handed backhand (I play with that backhand too). The Cortex Plus is a shorter grip and is better for a player who goes to the net alot. I have the Andy Roddick one and I love it because I hit Hard surves and a two handed backhand also love it for the price I got it for $50 bucks from my friend got it used with brand new strings.....hahaha got a steal on that racket.