matey, i've had 13 silvia's over the last 12 years, japster and silviagod have had many s12's as well and for longer than me, they will all tell you that they are fine on 97 octane and 95 octane if you don't boot it,i did 45k on my 305bhp silvia, it was fine and not valve wear , as long as you get your afr and timing right, then you will be ok,leaded and 5 star is real old school, rover 2.2tc springs to mind lol, most people on hear know there onions and you won't go far wrong mate,
