Think of MR12 as highly oxgenated 93 pump. 16:1 static compression is high to run 93 octane. I've got a 1340 gen 1 that has a static compression of more than 17:1 that I have run C45 with. For giggles, I check the HP on my dyno running MR12. MR12 picked up 3 HP above C45 on the first pull. When I got heat in the engine on the 2nd pull, it dropped 10 HP and showed signs of detanation in the graph. I ended running Q16 on that engine.