Ask MF: Is 87 Octane Ok?

A question we spent some time on during Woofcst 279 is this one by MF reader Richard.

I am interested in purchasing a Mini Clubman. My question is, What type of mechanical problems will you encounter by using 87 octaine fuel in The Cooper Clubman?

According to all of the official documentation, running 87 octane should not cause any problems in a Cooper Clubman.

That being said, I know from previous experience in my R50 that running regular unleaded gas resulted in lower fuel economy, lower power available and some knocking/pinging while driving uphill or under any kind of load like driving up a freeway onramp.

I have not tried this in an R55 or R56 but hopefully one of the fine MF readers out there have and can report back in the comments below. Especially helpful if you can tell us your experience running 87 octane fuel in your R56 MINI Cooper or Clubman Cooper, Not R56/R55 MCS.