@P Rock, I definitely had the CEL/Check VSC come on several times in the past few months. Granted it was before my carbon build up TSB was fixed, but the code reader showed code p0420. Haven't had the light come on since the recall was done, but given that I had a hole/broken midpipe, I'm sure it had something to do with it.

I got my code reader off of amazon for ~$20.