Working on purchasing an awesome bike; Seven Odonata. I'm planning on swapping over the Ultegra triple from an older (but not too old) bike to the new Seven to cut some costs. I'd like to upgrade some of the Ultegra to Dura Ace (still triple) at the same time. A shop suggested to me the best components to upgrade would be the crank set, rear derailler and shifters. Would enjoy hearing opinions, suggestions from anyone with first hand knowledge of these components as far as performance, durability...

Thanks

I would suggest that D/A BB's and chains be avoided. Both wear very fast, and the BB is quite fragile, expensive, and poorly insulated against dirt. Likewise, D/A brake calipers are quite expensive and flimsy.
OTOH, D/A derailleurs are quite durable and well-made. The rest would be more cost-effective if they were Ultegra.

You may need to replace the front derailleur also.