We haven’t tried the specific ones you’re asking about, but we have tried cylinder head replacement kits (for repairing multiduct gasket coolant leaks). We bought 7 from Global Marine Power earlier this year. So far 5 of them leaked and had to be replaced after about 6 months. Everything in the kit looked and worked good except for the red sealant around the coolant port on the multiduct gasket. The red sealant was paper thin, where Wartsila’s is very thick. I wouldn’t be nervous about using their products for side cover and valve cover gaskets though. They are much less expensive.