better confirm that is $899 for a pair before jumping in. The ad says heads, plural, but there is only a single one in any of the pics which leads me to believe it's per each. Still not terrible considering the potential.
I may be mistaken but I think some of those heads came without seat’s because many guys run titanium valves and they require different seats. Valves are not included either which is why I would change out the guides and get better valves.