I ride a Trek 1000C. It has Shimano Sora TripleDeck brifters on it. For the price I paid, its a great bike with a Sora 8 spd. The only downside is that it's impossible to downshift if I'm down on the bullhorns due to the placement of the little button that downshifts. I have been looking at upgrading to some Ultegra or 105 brifters. In particular, i have my eyes on these two
http://cgi.ebay.com/Shimano-STI-Shif...item20b0864e2d
and
http://cgi.ebay.com/Shimano-STI-Shif...item20b0864e81
I know relatively little about brifter history/quality hierarchy. Could someone more learned than myself enlighten me? Thanks!

Brent