Bell Canto C5i Integrated Amp with B&W Nautilus 803 Speakers. A Question

What is the size of your room, and how much room do you have behind your speakers?

that said, those speakers can be very forward and bright without the right amplification. Mating that with a 60wpc Class D amp is likely not going to result in a bold or warm sound. 

Besides room size, treatment and placement, how loud do you listen? I used to have a BC C5i that I used with ~88 dB efficient speakers (first Spendor SP 1/2E and the Golden Ear Triton 7s) in a medium size room and had no problem listening at average levels of 85 dB or so.  It is when you really want to crank things up (mid-90 dB or higher) that you really need the higher power amps. Remember that watts / sound level is a logarithmic relationship, not a linear one. For example, if it takes you 1watt to hit 75 dB, it'll take 10 watts to hit 85 dB, or 100 watts to hit 95 dB -- in other words, power requirement goes up 10 times for each 10 dB increase in listening volume.

Final suggestion -- invest a few dollars in a sound level meter or sound level app for your phone.  That is the best way to get a good idea of just how loud YOU listen.  Remember that one's person's "moderate" volume may be "extremely loud" or "soft" for others.

Yes make sure it can go loud enough otherwise c5i is a very good sounding and versatile choice.