modern Heads...nice ..no need to do anything they have hardened seats
well if compression (dynamic) is say HIGH you need to look into a different dimension...there is a nice wite up by George on gas oct match to compression..in case it might go into ADDITIVE direction ..or dif gas..
( I am lucky we have 98 oct..super+..so a free ride but more cost ..)
You have 98 RON
I want to move there