Welcome to our forum.
I'll chime in my 2cents. From personal experience, I would prefer an insulated cabinet instead of a foam shell, or better yet, a combination of the two. I have a foam shell (2000 Sundance) and I have had a few times where the circuit breaker tripped and shut the tub off. The water in the shell stayed nice and cozy, but the service area was vunerable to the cold and the tee housing with the flow switch swelled and cracked. Caused me a mess in the dead of winter.For pumps, I prefer having a dedicated circ pump (even if they can be a PITA), and then depending on how many will use the tub you may want 1 jet pump or 2 jet pumps. I like 2 jet pumps because I can have 2-4 people in the tub at any time and I like that extra water movement on all available seats and floor.