I used 601 for front and CC6 for center when I first purchased the 990. They were a good match for the pre/pro. But then I knew I was missing something and the answer was Swan 5.1 speakers... I could not believe how much of a difference it made from moving from 601 bookshelf to floor standing speakers.

I love how B&W speakers sound and wanted something close to it and Swan speakers gave me that with better soundstage and imaging (moving from old B&W 601). At least to my ears.

Have fun and enjoy the 990 and 602. It should be a good combination.