So i am getting ready to pulley down and i read somewhere that you shouldnt drop to a 3.4 if you cant get higher than 91octane gas. My current mods are cai, zzp1.0 pcm, 180*tstat, ported front manifold, 3'dp, and zzp hv1 tb. I live in colorado and we can only get 91 around here so would i be knocking with a 3.4, those mods, and 91 octane gas? I would have the car dyno tuned after i dropped but idk if that would make a difference in the knock. Or should i just play it safe and get the 3.5?