A rebuild kit is going to be largely gaskets with a few oil seals
thrown in. I've not bought one from eBay for a marine
engine, but have bought several for small motorcycles. I'm inclined to be neutral on the issue of China
as a source. When I'm purchasing a kit, I look carefully at the photograph to see what is included. So far, no problems, and yes, I find throughout that manufacturers overprice parts that are off the shelf from other sources.