This was my experience of bi-amping etc:
Cyrus 8XPd in integrated setting is baeline
XPd + one X Power (so bi-amping) improvement factor of 2
XP d pre out to 2 x X Power in mono improvement factor of 5
This was with a pair of Spendor A5 I was really impressed with the mono bloc set up, I wasn't listening any louder, but the sounds just opened up with much better dynamics and space around each instrument. However, to put it into a real world context a stupid amount of money for such little absolute sound improvements. Going from my previous NAD / B&W system to my current was a much much bigger jump in sound quality.
I'm increasingly cynical that top end hi fi is just taking the wee price wise, I understand the need to recover hours of R&D cost amortised into a selling price and all that, but there are plenty of business models of high price / low volume vs low price / high volume for the same product cost to market. Are you really getting VFM on anything over £1k let alone £2k?