Amp for KEF LS50?

Hello Folks,

I am searching for a decent amplifier for my new KEF LS50, a pair of exotic monitor speakers. Based on my investigation, I decided to have a Musical Fidelity amplifier. It seems there are 4 different options in my limited budget:

a) New 1 x Musical Fidelity M1 PWR (use it as a stereo amplifier)
b) New 2 x Musical Fidelity M1 PWR (use them as monoblock)
c) New Musical Fidelity M3i
d) Used Musical Fidelity M6i

It seems having M6i is a overkill to my speakers. So, the real competitions are among the first three options: a), b) and c). The core question is that I don't know how much improvement I can expect by using two M1 amp as monoblock against option a) or option c) specifically for KEF LS50.

Looking forward to getting an advice.
FWIW, I use mine with a MF M3i but the only other amp I've listened to them on is a NAD. I'd really like to hear the Kefs with a tube amplifier. Compared to the Harbeth P3ESR's which I also have, the Kefs seem to have less dimensionality than the Harbeths and good tube amplification should improve this.

That said, if you didn't directly compare the two speakers ina a system and room that you were familiar with, you probably wouldn't even notice it.
I listened to a set driven by Granite audio monoblocks. The sound was very good and highly dimentional. A great match. Best
I just purchased a pair of the M1 PWR amps to bi-amp my Totem Hawks which have a top power rating of 120 watts. I was using a Pass Labs X150.5 through an Audio Research LS2 pre, but thought I might overtax the speakers so...Great deal at Music Direct for the pair, $799!