Priorities...

I only ask about your music tastes so I can understand why you make those statements. 
I listen mainly to progressive technical rock/metal & math rock so I need amps that provide very high levels of detail & speed but tonal accuracy; the GamuTs are excellent at providing these requirements. 

I've been offered a pair of ARC Ref 210 at a good price & so have thought about selling the GamuTs & Tannoys to buy them & the new PMC twenty5.24...!

@bombaywalla - I agree! I particularly like the iron fist/velvet glove metaphor! 

The M250i are also very sensitive to mains upgrades so I suspect I have yet to hear their full potential...

@bombaywalla ...we'll just agree to disagree, how's that?  The Tannoys don't need lots of power, you just want lots of power. Difference!  Our experiences obviously differ.  It's based on listening preferences, room size, etc.  Go back and read through all the advice here given to the OP to stay on track.

@infection, if you're in love with your amps and are seeking affirmation on how good they are then just keep them.  You started out by seeking advice yet give very little detail as @goheelz mentioned.  When I gave you advice based on my experience with Tannoys, which is extensive, you end up defending your amps which is missing my point.  Regards.......

@infection also, you mentioning the ARC amp and PMC speakers further suggests to me that you just want to try something different out.  That's why I asked you if you really liked the Tannoy's.  As my friend JohnnyR has told me more than once, "you're chasing your tail".  Now that I think of it, do grab the ARC amp and a pair of Vandersteen Treo CT and be done with it.  Buy lots of music and no more tail chasin.  You can just sit back and enjoy.  Regards.......

@carmenc - relax dude, we're just having a conversation. This thread wasn't seeking advice but opinions. Difference! (Couldn't resist). I think you've missed what I mentioned re: ARC Ref 210/PMC.
Another option is the Alta Audio Rheas...