A question about Anthem amps?

No, there are vastly different...in both performance and price..

The 165 is enough for your speakers but I think you would be happier with the MCA 30. Much better design and more available current which is what Paradigms like. Decent value for the money.

I concur with Cosmic. I have the MCA 20 for my mains and the MCA 30 for my center and surrounds. My speakers are Monitor Audio Silver Series. The Anthem amps are a great match with these speakers.

I wish that I could afford the MCA-30, but the price, even used, is too high for my budget. I am looking at spending about $500. I am going to use the amp to drive Paradigm Studio 60s at first and then Studio 40 v.3 speakers in a few months. If I can not afford the MCA-30, should I go with the MCA-3 or look to Rotel and B&K?

How many speakers are you looking to drive with this amp? The MCA-30/3 are three channel amps. If budget is your concern I would consider getting a better amp and doing the front L-R with the good amp and using your (I'm assuming) receiver to power the rest of your speakers. Having said all this, if you budget is that limited and you can find a MCA-3 within your budget then jump on it and be happy.