Originally Posted by
Ziemas
Aside from maybe a saddle, which is a personal preference part, nothing.
Ride the bike and make sure it fits right, that will make a much bigger difference that any minor parts upgrade would.
Why would you want to upgrade a new bike anyway?
+1, get nice clipless shoes if you don't have them already -- to make riding clipless comfortable! get a pro fit if you can afford it. unless you're looking for bling the steamroller is good out of the box. like others said I wouldn't blame you if you wanted to ditch the velo saddle though. saddles are personal preference as much as pedals are, surly just threw on the cheapest one probably!