Does octane booster make difference in the car?

I have a new car,the manual of the car says 98 minimum ron...but only 95 octane is availbale at the place i'm currently living in...so can I use STP octane booster or Gunk one every time I refill my tank?will this octane booster harm any thing in the engine?or will just raise the 95 to the 98?