The C1's are 4 ohm so you are really pushing them with 700w per side. As a C1 owner I've never heard the C1's with that much power. I drive mine with an Octave V70SE tube integrated w/black box (70w/ch) and am very happy with the sound. The only amp that I prefer is the Burmester 911. Way out of my budget. Have you thought of an all tube amp? The V80 tube integrated is more than enough for the C1's. The re290 uses the KT120's. Tube power is a different sound. Another nice things about tubes is swapping them for other ones. When you think you want to change the sound a bit start swapping tubes. Much less expensive than buying a new amp - source - cables - etc.
That being said if your quite happy why change? Are there better amps/sources/cables? Always, if not to you but to somebody.
That being said if your quite happy why change? Are there better amps/sources/cables? Always, if not to you but to somebody.