The Anthem is hands down a nicer unit. However, I don't think it is 4-5 times as nice. You've got to sit down and decide if that extra teency bit of transparency is worth quadrupling the cost of your pre-amp. If it was me (and it isn't), I'd probably use that extra $3.5k to upgrade either the speakers or the source components first. The 990 is about as good as it gets without dumping big wads of cash. The Polks are a much weaker link in my view (but it's not my view that matters here...it's yours).

Sounds like it will be a nice system regardless of which direction you take.

Cheers,