twitchy handling sit CF fork
I agree that the head-set would be a good place to start looking. We bought a new co-motion mocha in 2007. In an effort to save money (I guess) the dealer installed what looked like thin walled electical conduit, hack-sawed to length, to make up a 2.5 inch spacer. Last month, before selling the bike, I bought a set of proper spacers and the handling really tightend up. A really big change in low speed handling from what seemed like a very small modification. On inspection, the dealer's home-made spacer was deformed as a result of loading.
Good luck sorting this one out.
Joe