The Bel Canto S300i is a good integrated, but the PRe3 and REF500S would be a substantial step up. If you're getting out of analogue, then you could definitely consider getting rid of the PRe3 and use a Bel Canto DAC directly into an amp like the REF500S. You'll improve your digital front end and with 2 half sized components (the DAC and amp), it will take up no more room than one full sized component.
Disclosure: we are a Bel Canto dealer
Disclosure: we are a Bel Canto dealer