HELP!! Upgrade from HD3 - HDX or Native?

[Rawbzzz]

Hello Everyone,

Firstly I would like to thank you for taking the time to read my post. I am thinking about upgrading my HD3 system for either an HDX or HD Native. I am struggling to determine which one is right for me and thats why I need your help. Firstly I would like to outline my current setup.

Mac Pro 4,1 Quad Core with 6 GB of Ram
HD3 Accel (As stated above)
Pro Tools HD9
3 x Avid 16x16 interfaces
1 x Digidesign 192 "blue" interface
1 x SSL AWS 948 Console

I use the 3 Avid 16x16 I/O's to output to the console (48) and the 192 to output to the Aviom headphone system (16). I will probably only use about a maximum of 24 inputs at one time when tracking but that could change depending on the project. I have 48 preamp inputs including the SSL.

The reason I want to upgrade is mainly a workflow thing. The Mac Pro is very sluggish and it can sometimes take a while to open up a large session with lots of plugins. Often it won't even open and crashes. I am now getting multiple crashes in 1 day of working which is so frustrating. I use quite a lot of plugins in my mixing sessions and I will normally max out the TDM engines before going to RTAS. I also want access to the new features in Pro Tools 12. (Clip gain, track commit etc)
I really want to run Pro Tools 12HD on a laptop with a chassis for either the HDX/Native card. I recently purchased a MacBook Pro 2,7 GHZ I7 with 16GB of Ram to kickstart the upgrade process and its obviously a lot faster than the Mac Pro I currently use in the studio. I want to open a Pro Tools session instantly and not wait forever for the sessions to open. I also want to have more power when mixing. I requested a quote for the HDX Core card and literally had to check my underpants after reviewing it! But fits the right way to go then I must commit. HD Native is also a great option but will it be powerful enough for what I need? Anyway thanks for listening and if anyone has any comments please can you post below. Many thanks!