Yes and yes, and you can receive amazing results with both use cases. As of right now, ALL modules are interchangeable between the two formats, with a caveat (see below).
When included in a custom using the standard Q build type, the Quintessence subliminal production system will automatically convert the Ultima Core’s script into a Q custom script. The thing is, Ultima programs were built to serve as fast acting boosters to your stack. This functionality requires the Ultima Core to be built in the ULTIMA format.
When you include an Ultima Core in a Q-Standard custom, the Ultima Core’s scripting will now provide long-term results, as opposed to the quicker (but sometimes shorter term) results that the Ultima format itself provides. Putting an Ultima Core in a Q-Standard custom DOES count as a core, so please don’t include Ultima Cores in a Q-Standard in an attempt to skirt the recommendations.
Keep in mind, however, that adding a Q-Core to an Ultima formatted subliminal will not turn that core’s scripting into short-term programming. With this use case, you’re essentially creating a very, very powerful Q-Standard subliminal due to the fact that the Ultima format itself consists of a masked subliminal with an embedded ultrasonic file (among other optimizations).