Find a way to upgrade the plumbing to one inch to get a boost, but itshouldshould not be necessary.
I doubt you'll ever need more flow, but if you do, a plumbing upgrade would be worth it.
In fact, upgrading to 1.5" plumbing for the return seems extreme, but it would completely eliminate friction loss, thus reducing headloss to the absolute minimum possible, which may be about 4'. (Measure your system.) This would be especially worth it before deciding on a pump upgrade, if that was something to be decided.