I know that Acura 'recommends' premium 91 octane. But since they only 'recommend' and do not require premium, does anyone use regular 87 and what are the effects? I had an Infiniti I30 that 'recommended' premium but always used regular and didn't suffer any performance or knockiing issues.

 

There are a bunch of existing threads that address your question. Try searching on "octane". Here are a couple to get you started:
https://acurazine.com/forums/showthr...ghlight=octane
https://acurazine.com/forums/showthr...ghlight=octane
Since this has already been covered I'm going to close this thread. Please post any follow up in an already existing thread.