Read and follow your Owners Manual.
You should be using 95+ since your octane is measured using the RON method, which is different than in N. America..

 

If only i could find that high of octane around here. i run the highest i can get which is 91 here

 

We used to have a lot of Sunoco stations around here. They carried 94 octane.But a bunch of them closed and all the others only carry 93 octane now. So I use 93

 

 

USA uses (R+M)/2 octane rating method. 95 RON is about 93 "American" Octane and 93 RON is about 90 "American" Octane.

 

I always use high test, 92-93, mostly because of high compression, and I keep a jug of Cam2 in the garage for special occasions. There's a small airport nearby that lets me fill up every once in awhile

 

The highest I normally come across here in So Cal is 91.

 

I use 95. Figure $15 a fill is not too bad.

 

I've been using 89 for 80k in my ultra and it runs fine. Higher octane is used with higher compression to prevent detonation. Higher octane won't give you anymore power or performance without mods or severe altitude changes.