I am using "87 Unleaded" gas on my car right now. If I were to change it to 89 or 91 Premium gasoline, will it affect my cars engine or will it be okay? I heard that the Premium gasoline will make the car run stronger??? and etc...

Can't say you'll notice a difference. I switched to 89 octane because its been over 100* here everyday. It "seems" to idle smoother, and "seems" to have a little more pick-up from the red light. I was looking to make sure I don't get any pinging with this hot weather. Pinging will cause the timing to be retarted by the ECU, so gas mileage may come up.