Us and euro gtr can run ron 95 but factory mapswill cut output, with cobb ap you are able tune the engine to run 95. I've got mine tuned at 1 bar stock everything 480whp and 1.2 bar 500whp however advisable to go 97 with that map.
Basically, the belt started to give me the annoying "chet chet chet" sound whenever it gets hot. SC says no need to change since it will cost a lot if I let them touch...