Just thought I'd post some pics of my Rainbow Pentair 320 Installation.
Here is my original plumbing setup. As you can see, everything is pretty tightly crammed in.
Given the installation requirements according to the manufacturer, I was concerned about 2 things: Not having enough straight pipe leading up to the inlet, and being able to remove / salvage it if necessary. Both of these would necessitate me re-routing the pipes a bit.
Through numerous trial and error attempts, I created a 'dry fit' assembly of what would need to be replaced.
Here is the section I cut out. I made sure that the cut points allowed me enough room for couplers.
I assembled the parts so that the last part would be the end segment closest to the pump that I would cap on at the end. This way, I wouldn't have to try to wiggle pipes into place and everything would fit good and tight.
And here it is all assembled.