Re power choices for Sweden 36

The 28Hp VolvoPenta 2003 saildrive in my Sweden 36 still runs, but is inefficient, expensive (parts) to repair, sooty and struggles mightily in a 20kt headwind. We motor frequently in Puget Sound; it's just the way it is. On a day headed south in the summer with a light breeze aft, the cockpit stays filled with strangling vapors. I want to keep this boat and enjoy it more, and have been advised by mechanics not to invest more in the old Volvo. I am near two boatyards, one which I know will assist me in a DIY project. Replacement choices are sail drive models of a 38hp and 28hp Yanmar, a 28hp and 40hp Volvo and 28 and 35 hp Beta Marines. The 28 hp motors with saildrives from Volvo and Yanmar would fit the engine bay without cabin mods. Both Beta Marine units take up more space than I have without extensive mount and engine cover reworking. The more powerful Volvo 4 and Yanmar 3 units could be fit (at first glance!) with a 2" extension built into the engine cover that would impinge a little on floor space, but would be a worthy compromise for the reserve power. I am leaning toward the 38hp Yanmar at this point. Your thoughts?