Choosing right spec 15" MBP for logic pro x

Hi,

I am going to get a new 15" MBP but can't afford both the GPU and CPU upgrades.

Are there any apple audio experts out there who could tell me whether it is best to upgrade the CPU from 2.6 to 2.9 ghz or upgrade the GPU from bass model to 460 specifically for improving LPX performance please ( any chance LPX will support accelerated graphics like final cut soon? )

I have read that there will be little difference in performance between base CPU and 2.9 ghz especially at full tilt and max temperature due to power throttling on the 2.9 for reliability due to higher temperatures ?

Does logic pro X 10.3 use accelerated graphics tech and so will benefit from upgrade in GPU ?

I've also heard of GUI issues in logic and reaper so wondering if increasing GPU will help ?

I can only afford one or the other as i must get 1 TB of storage this time i think.

I know very little on this subject and this would be a one off purchase for me so i must get it right.

I would really appreciate any professional or experienced help.

thank you.