Volvo Penta 4.3gxi manifold and riser replacement

[Monster1]

Boat is an 04 with original exhaust parts. Engine has approx 250 hours with 80% freshwater usage to 20% saltwater usage. I flush the engine after each use. Never drain the manifolds to winterize. These are the pictures from the starboard side when I pulled the riser to replace the starting battery in the engine compartment. I thought they look good and was going to run them for another season but showing them to a reputable volvo repair guy, he said replace. He said go either OEM or Sierra. OEM is about 1400 bucks. Sierra is only 200 less. Barr is about 600 less and made in USA like PEN as opposed to Sierra which is made in China. I'm leaning hard toward Barr. Opinions please?