new Dura Ace crank
 

I have bought a new bike with Ultegra shifters and Ultegra 10 speed cassett.. 11-23.. it came with a FSA Carbon pro compact crank and I want to change it to a Dura Ace double 7800 .. standard.. crank.. Does anyone think I will run into any trouble with the meshing of the ultegra cogs/chain, front derailuer and the new DA crank.. I know I will have to move my front derailure up a little, but i am concerned about the cog spacing and the chain width ...

All DA/Ultegra/105 10s stuff is interchangeable. For example, you can run a DA chain on Ultegra front rings through a 105 rear mech onto a DA cassette with no issue. This is fine.

You will probably need a longer chain.

hey thanks I hadnt thought about that.. I will need a longer chain..

Or in my case, DA shifters and BB, Ultegra front mech, Ultegra chain and cog, 105 rear mech. Oh, and RSX brake calipers. ;)

This is completely up to you, but you MAY not like the higher gearing that comes with a standard double crank paired w/an 11-23T cassette. You'll essentially lose that very lowest gear (maybe gear and a half) you currently have.

Even better!
I hadn't thought about the chain either to be honest, good call that man.