Do you know if I can run both components at the same time? I can't afford to lose my paying members and do not want to ask them to have to sign up for another monthly membership.
I don't see why it would conflict, but have never tested nor heard of it. I would stop renewals/new subscriptions on your previous subscriptions management software so when users need to renew or subscribe it would be through CBSubs instead. Once everyone has expired from your old system it would be safe to remove.