Can't help feeling this has been covered recently already.......but here goes.
As good as the Spendors are, they're not exactly rock speakers. They're the smoothest speakers around, so tend to need lively amplification to inject a bit of energy into them - something like Cyrus. The Tannoys I can't comment on, but we will have a few on demonstration over the next couple of weeks. The XQ40's should work ok with the K2, but also try the Naim Nait 5i.
If you like a smoother, warmer sound, you may well prefer the Spendors, but whenever I listen to rock, it just doesn't sound right to me if there's not an 'edge' to it. It's like the opposite of hearing some nice relaxing classical music on an energetic, bright/harsh sounding system - not quite right. The Arcam A18 is also worth a look if you like smoother tones, but partnered with the Spendors will be too smooth for many.
In some ways there's no right or wrong, only personal preferences. A demo is therefore recommended.