Is Cakewalk's CA-2A compressor only for those with Sonar Producer? I'm running Studio X2 which does not have the Pro-Channel. Am I SOL?

It comes with a VST version, too. You would be able to use that.
 
I highly recommend it.

I like it also. Easy to use great results.

Please educate me - what do you mean by VST version?
Thanks!

The CA-2A is not just a Prochannel module, it also comes as a VST plug-in that you can use in the FX bin. From the store page:
System Requirements:
• Mac OS X 10.7.5 or higher [64-bit only]
• VST3 or Audio Units compatible host
-- OR --
• Windows 7 (SP1) [32/64-bit], Windows 8 [32/64-bit]
• a VST 3 or VST 2.4 compatible host, SONAR X1 Producer Expanded or newer for ProChannel module
 

Vst is the generic version and will work in any vst host :-) you should get to know about vst ;-)

lawp
Vst is the generic version and will work in any vst host :-) you should get to know about vst ;-)

Yes, thank you. I should indeed learn all I can!

Good learning resources include www.kvraudio.com and www.soundonsound.com - have fun! :-)

Here's a decent source for that info: http://en.wikipedia.org/wiki/Virtual_Studio_Technology

get it get it get it.