use the search button
also
it help to list your mods,IE*pipe,filter,elevation,temprature you plan on ridding in* but generally compression shouldnt change your jetting, when in doubt do a plug chop. also 155 to 160 run 100 octane or 110 or whatevers avalible, youll be board edge, just see how it runs, if it feel likes its pinging then try bumping down to 21cc domes, but truely 20s should be fine.