Originally Posted by Menel

It's possible, but I suspect there are other variables.

My bike came with:
Tiagra shifters, Tiagra FD, 105 RD, FSA Crank, Sunrace Cassette, KMC? chain.

Upgraded it to:
105 5700 shifters with new Shimano cables, 105 5700 RD, 6700 Cassette, 6700 Chain, left the FSA crank and Tiagra FD.

The old stock tiagra setup shifted way better. I actually just got through posting about this over here:
http://www.bikeforums.net/showthread...1#post11806322