type r sti 5 v ltd power output
 

whats the correct standard power output of this model i've seen several different outputs quoted? (276, 280, 296 etc)

276ps i think,not sure there is a v limited version 5 though,just limited version 5.

that was the agrement they had in japan(276)but the car actually put more power out than that, now done away with

All the post 97 JDM Impreza's were 300ps which is 296bhp

All JDM power figures are based on using 100+RON fuel don't forget.

would it be the same running optimax with millers octane booster?

All figures are set at 276bhp (280ps) as this was a gentlemens agreement in japan, post 1997 cars run 276bhp as standard, some may run more, some less, not many run 300ps in standard form.
Hope that answers your question :D

Tony:D