Someone I know, i had the stuff for a little while when i was gonna build the ring 20 last year.
I can get you a 20" offshore mid with trim pump and a 20" gearbox. It's not a sporty, but with my past boats I've just tapped in a transom pickup instead, that way you never have to worry about engine height giving a good enough water feed. Should your impeller fail I'm sure a transom pickup would still provide enough water pressure, and that way you've got two totally seperate pickups too, the transom one and the standard one, as a failsafe should one become blocked.
I'm sure you'd be able to borrow the leg and box pending purchase to see how it goes and save you wasting any money
My old 2.5 200 was a very pokey motor with skimmed heads and exhaust chest porting, plus it was super reliable. I'd say that's quite a good option!