I have a Universal M4-30. The elbow that came with the engine wouldn't fit the space but that Yanmar part does the job quite nicely. Here is a poor quality cell phone shot I took this afternoon with the riser/elbow assembly removed. The engine box top starts just above that wire run. The water lock muffler is tucked into the keel as low as I could get it. As you can see, the bridgedeck bulkhead and keel space limit my options. The waterlock muffler didn't look too bad either but I'll drain it and give it a good visual inspection anyway.

Glad to hear your onboard enjoying your boat, Gene.