Is all of the plumbing run inside the tub or does it go underneath the tub. The way we got it there was Plumbing inside the tubIt's pretty simple, and it's a large heater core as it's the full circle...pumps out quite a bit of heat.
At least as much heat from the rear as the front, as it's a bigger core than what's in the center/front box. The fan is a bit funky, but you don't need to move that much air to get the heat transfer.
The rear heater puts out a decent amount of heat. I don't need it hear in AZ but in Colorado the additional heat was welcome. If you have all the parts and the core is good, why not put it back in.
No need for it in TX, further north in Montana, heck yeah.