If you got the budget. Buy the best i7 on the market today, and graphics cards
MEMORY since as far as i know , p3d and fsx are both 32 bit , so 6 gig will be more than enough 4 for the game 2 for the os as long as the os loads high and is 64 bit ?? Need clarification
Dual channel memory so sticks in matched pairs
Nvidia titan 2 of them in SLI.
Cheapest titan i have seen is about 600 GBP