I'm in Australia and 87 octane seems a bit poor, I would never go that low.

Our Standard Octane Rating for Regular Unleaded is 91, and we have a middle grade of 95 and Premium is 98 octane. I own a non turbo Supra as well as a VX and I always use 98 octane (shell optimax) in both cars, another good premium we have is BP Ultimate.

I have found a big difference in power and economy, and the engine seems to run a lot better too. It may be dearer at the pump but you will also get more range out of your tank.

My advice would be to always use the higher octane.