What AV amplifier for 4 x b&W + centre

The Mac is pretty old tech without getting the brand new one. The Arcam you already have is pretty nice. You could move to the Arcam AV860. Another option is the more traditional route of the Marantz 8805. I like the frequent updates from Marantz. It’s a really good processor and will be rock solid. 

Thank you Guys.  
I will look for a dealer i can hear McIntosh and let you know my thoughts 

Hmmm, just be aware that most dealers that have the MX-160 will likely have it all hooked to only McIntosh amplifiers.  I do know for a fact that the Mac amps are very laid back in the midrange (and overall).  It will NOT sound like your Classe 5300 and you could actually be dissappointed because of the lack of excitement from the Mac amps.  This may or may not be a result of the MX-160 processor, so if they can hook it to higher resolution amps, it will give you a better idea of what it will sound like in your system.

@mayoradamwest - why would you call MX-160 old tech?  It does use the new Lyngdorf DSP/processing hardware.  

The MX-150/151 is the "older tech" platform.

The 160 is nice and if just using for pass through it’s probably fine but lacks the latest HDMI HDCP 2.3 and most of the HDR formats like Dolby Vision.