In my earlier system I went all the way up the Naim amplifier chain to the NAP 500DR and the 552DR together with the 101 tuner. Between them they took up a helluva lot of rack space and with the separate power supplies a helluva lot of cables.
A chance discussion at Munich some years ago motivated me to try a Vitus SIA 025, despite my doubts about its power output. The Vitus sound quality was significantly better and the power output was entirely adequate..The decluttering benefits and cable demands were very welcome.
A couple of years ago I upgraded to the Vitus SIA 030 which is even better though obviously more expensive.
I have not heard the integrated Vitus Reference series in my home,but only at demos and they too are very good, but not as good as the Signature series I have or had, which reflects their lower price. Here in the UK the Vitus integrated amps hold their value well which is a big plus. Depreciation can be very costly when you come to upgrade.
Vitus do have their separate pre and power amps, but I am entirely happy with my integrated 030.