Hi Ccn
I have a cannondale caad8 sora triple and would like to upgrade. The only upgrades ive done is change pedals to nice flat commuting pedals and added a shorter stem and upgraded the wheel to some special offer shimanos what the next best upgrade for my bike.
IMHO wheels are about the biggest improvement upgrade you can make to any bike. I know you've already changed them, but with respect you're not very specific about them, and they clearly don't excite you. I don't doubt they where an upgrade to the stock wheels, but I'd wager they are still worth upgrading. You could keep the Shim's as winter/training wheels.
Also, I'd swop the triple chainset for a double, (compact if need be), this will certainly save some weight. I've personally never seen the point of a triple on a road bike. Your own fitness is obviously a factor in this.
Sora is a dependable enough workhorse, but I'd look at starting to upgrade this as you go, I'm not suggesting you go and buy a Dura-Ace groupset, just upgrade components as and when they need replacing. Personally I'd avoid Dura-Ace and stick to 105/Ultegra, (I've no experience of Campag or Sram equivalents).
Of course, any of this depends on your budget, your own taste/preference and also the cost of upgrade v buying new bike equation.You dont say how long you've had the bike, Cannondale do a frame swop programme that reduces the cost of a new frame when you exchange your existing frame, so you could look into getting a CAAD9 or CAAD10 frame perhaps.
These are just my personal thoughts, some will agree, some won't. Why not join a club? Get out with like minded cyclists, see what they ride, get their ideas, see various components in action.
Ride safe
