Helix, yes I'm using the spikes through the carpet although I think they need to be longer. I've also tried on slabs too. The difference is minimal in my room, maybe a slightly more focused mid bass on slabs, but the bloating still the same, although I know from past experience in previous rooms and systems that this can make a good difference.
I'm using a Cambridge Azur 851A. I've compared this side by side with the Arcam SA20 in my set up and room. They sounded very similar although the Cambridge just nicked it paired with my 2 DACs - RDac and SMSL M500 Sabre Pro. It was very close. The Cambridge sounded a touch more agile on some recordings. I also chose the Cambridge due to it having tone control, which I value to use on the odd poorly produced source material.
I think my issues are mainly room related causing bass and mid bass bloating and the drowning out of highs and possibly upper mids.
When I demonstrated the Oberon 5s they sounded superb, beating speakers bigger and more expensive, so I'm reasonably sure it is a lot related to my room, although I'm thinking some of the better metal dome tweeters might be good for my faster metal music. The Cambridge Audio CX80 amp I switched to part way through the demo also blew the £1800 amp we started with out of the room too. Nothing is guaranteed on this journey!!