I'll poke around for a host after I get home tonight but until then, here is an image of the decoupling. You need to let it float free of the decoupler after triggering it. For some reason, possibly the quantum struts, it didn't allow me to turn ship. It just yanked it right back until it floated free. Any new engine unit or other module would need a docking port because I only used a decoupler for the engine section to get that damned hump correct. I also might have forgotten RCS ports on the cockpit section. But the ship has plenty of delta V (20 minutes if you turn off the Poodle, 5 minutes using only the poodle, 13minutes with all engines) for anything you can outfit it with and the cockpit section might become the basis for a modular system.