I used to drive a Subaru Legacy 4-Cam Turbo ( the turbo nutter thing before the days of the Imprezza) and got miffed one day when some 2 litre GT jelly mould thing burnt me off at the lights one day :-( .
I took the car to the dealer mentioning that I was suffering from poor performance and they ran every test under the sun including plugging a fancy box of computerised tricks into a socket that was dragged from under the dash (hot wire style)..."the rally boys tune theirs like” this the technician said…any way to cut a long story short after noting that there was nothing wrong, but agreeing that it wouldn’t pull the skin of a rice pudding (so to speak), the guy asked what fuel I put in it and where did you get it from. Regular unleaded from the supermarket I said – it’s the closest to home!. After he got up off the floor, he advised to use a ‘proper petrol station’ and only use super unleaded. If it didn’t cure the performance I should go back in a week or two.
Needless to say it transformed the car into what it should have been before. I don’t know why or how but I never did take that trip back to the dealer after a couple of weeks! Yes it cost an arm and a leg, but boy it was worth it.
These days I’d like to think I’d grown up a bit and I can’t stand the nagging about pointless extra fuel costs etc…but I still feel there is some truth in the proper petrol and super grade unleaded story – especially if you have a performance car. However, I’d argue that the RX isn’t exactly a performance car (3.0V6 or not)…you pays yer money, you takes yer choice!