X1400/V5250/Advanced Dock PCIe Card-battery life/performance

[blynch]

I've exchanged my T60p due to bluescreening issues, and I am having second thoughts now and am considering changing my order. I only got a little over 2 hours with a 6cell on the T60p, so I am considering the T60 with x1400. For starters what battery life are people getting on a 6cell with x1400?

Two options:
1) T60p with mini dock
2)T60 X1400 with advanced dock and a PCIe graphics card

I know the PCIe is limited to x1, but even so how would a decent graphics card in the advanced dock compare to the x1400 and v5250?

If a PCIe card in the dock would run as fast or faster than the v5250, and the x1400 gets noticebly better battery life, option 2 looks excellent. I only need the extra power at the desk to play games.
If it doesn't run as fast as the v5250, the x1400 doesn't get much more battery life, then option 1 is better since it is also considerably cheaper.

edit: I saw some numbers from a previous thread about running video cards from the advanced dock, but they were with older machines (aug) and I wasn't sure what to conclude from that thread except that the PCIe is limited to x1.