Just checked my '15 300 @ 12k miles. Intakes were good 7,8,8,8. Exhausts tight 8,9,9,9. Checked shims with Venier and got rough numbers so I'll barrow Mike for better numbers. Checking with magnifying glass showed an 8 & 3 on three shims and nothing on forth. I'm 2nd owner so perhaps it was clearanced before with non oem shims. Checking prices I found oem as high as $13+each and Moose brand at $1.95(misprint?) from Dennis Kirk. Are these exhaust valves welded 2 piece units that lose head hardness during welding like some Hondas had? The face and seat must lose metal for them to tighten up right? Thanks,GJ