Hi Tim,

I was wondering how much the newer models added other
than subwoofer
control.

The subs are only on the RCS 2.2X. The RCS 2.0S has
twice the frequency resolution of the RCS 2.0, but
that's not a big deal.

My new Linkwitz Orions already go down to 20Hz so I
don't plan on
adding a sub.

The advantage of the sub channels of the 2.2X is that
the subs, or preferably corner-woofers like the W210's,
can be placed in the front corners (if you've got
them). I have B&W801's, which aren't bass-shy either,
but adding the W410's made a huge improvement in the
bass because of the corner placement, which is the best
place for woofers but only if there is DSP correction.
Next best is dipole woofers, but they don't work in
corners. Stick a Thor in each corner.

The refurbished RCS 2.0, at $1500, was already the
most I was
willing to spend for a new preamp. Has anyone
actually done a blind test of
the 2.0 and 2.2X using the same room curve? I wonder
how much, if any
difference there really is.

I had an RCS 2.0 before I got the 2.2X, but I didn't
compare them because I also added the W410
corner-woofers, which made an order of magnitude
difference. But I wouldn't tell you to upgrade from
the RCS 2.0 to the RCS 2.0S. I sold my RCS 2.0 for
$1900 three years ago, so I think you got a great deal.

Regards,
Tip