Anthem processors: AVM20 v. AVM30 v. D1

I am building a new system from scratch for HT and music and have liked what I've read about the Anthem processors. While I can afford to buy the D1, I also don't like paying a lot more for marginal improvements, and from what I've read, the AVM20 with upgrades is so good that upgrading buys some improvement but there isn't a lot of room to improve.

For those of you who have owned or used the Anthems, how do you evaluate the enhancements compared to the added costs, both in 2-channel and HT? What does an upgraded AVM20 used go for and how much more might I pay for the 30 or the D1? Would it be wisest to get the 20 and if I want to upgrade wait until the D1 is replaced and becomes more widely available used?

As an aside, I'm pretty set on getting a DD Velodyne as the sub while my choice in speakers is still wide open (I need to foind more time to listen to speakers).

Also, any suggestions for mating the Anthem pre's to an amplifier?

Thanks for your suggestions.