Happen to have the exact same bike. Bright yellow right? 7sp really is fine, I've upgraded my bike to 8sp but that was strictly a by-product of my Dura Ace upgrade. High quality frame, I love mine. I ride mine to school, work on nice days, and have done some Tri's with it. 400 is too much. I bought mine for $260 shipping included. With the RX100 components that came with it that just seems like too much unless everything is in absolute pristine condition.
Jeremiah