double check that HSF and that RAM , to make sure there is enough clearance ..occasionally , certain HSF and RAM with hi-rise heatsinks wont 'fit together' ..otherwise I dont see any problems ..but others may know more than me
There are low profile Vengeance sets, personally I think changing to one of those (if that isn't what Nick originally selected, it's hard to tell when no model number was posted) is the better option. The G.Skill Ripjaws and Ripjaws X sets are also short enough to fit under the Noctua NH-D14 - which is by far the better choice in terms of temps and noise.
Also 850W is more than enough for an OCed system with two GTX 560 Tis, such a system won't even 'overload' a 650W PSU, so money saving or increased quality could be had for the same/similar price if you wish.
As for 'cords': the motherboard will usually come with enough SATA connectors for a basic build, but high end motherboards like the MSI P67A-GD65 or Asus P8Z68-V Pro come with four. All power cables are provided by the PSU. So I think all the cords you'd need would come with the components.
usually all of your cords will already be supplied, you might review the case and see if anybody has had trouble getting a cpu power connector to reach from a psu, i ran into that problem with my asus board last time, just got an extension cord for the cpu power connector, i am very picky regarding cable management although, Lol.