[Solved] Which asus motherboard/chipset should I choose. P67 or Z68?

Which Asus motherboard should i choose the
ASUS Maximus IV Extreme-Z ROG Motherboard - ATX, Socket H2 (LGA1155), Intel Z68 Express, 2200MHz DDR3 (O.C.), SATA 6.0 Gb/s, RAID, 8-CH Audio, Gigabit LAN, SuperSpeed USB 3.0, CrossFireX/SLI Ready
The ASUS Maximus IV Extreme-Z ROG Motherboard pioneers new overclocking methods to enthusiasts.
$379.99
or the
ASUS Maximus IV Extreme B3 RoG Edition Motherboard - Socket H2 (LGA1155), Intel P67 Express, 2200Mhz DDR3 (O.C.), SATA 6.0 Gb/s, RAID, 8-CH Audio, Dual Gigabit LAN, SLI/CrossFire, USB 3.0, Bluetooth
The ASUS Maximus IV Extreme offers the Best Overclocking Experience on the new Intel's Sandy Bridge platform featuring the Intel P67 Express chipset.
$359.99

I think I understand the difference. Tweaking the GPU is only allowed on the Z68 chipset. The thing I don't understand and maybe I have this wrong but, If the motherboard doesn't support on board video does tweaking the GPU meaningless? I have a perfectly fine Sapphire 6870 Video Card and I know I cannot tweak this card from the bios. So, in other words what is its value to me.
Note: I will be trying to overclock if possible to 5.0 Ghz + if possible. Also, I do run adobe photoshop and other video editing software as it.
From what I read and tell me if I'm wrong that, unless I need the GPU tweaking feature on the Z68, when overclocking it is best to be achieved using the P67 Motherboard.
Thanks the Noob.

P.S. I do like the fact that the P67 board is $20.00 cheaper.

I Have the ASUS Maximus IV Extreme-Z and love it. If you don’t plan to edit video then you won’t be using the lucid system, but as the software evolves you never know. And for the Intel ssd crap, just buy 120g ssd and 2 wd black and RAID them. I heard a rumour that the new Intel ivy bridge may have some tweaks that the P67 can’t use Vs the z67. And 5.0 no prob just get good cooling. My system at 5.1 is running at 23.C idle and 60 to 63 load.
Ps/ I payed 356.00 for mine

How come you want to spend so much money on a mobo? I Should recommend you the z68 mobo. maybe some day you want to use your ssd as cache and maybe you will get a better gpu. If you are so eager to save $20 why do you want to buy such an expansive ombo?