ubercooper

factory sticker in my 89 2.7 n.a says 91, as well

Whitt944

My 88 runs badly with anything under 91 in it.

yellowline

91 RON. We use a different octane scale which runs 4 points lower. 87 is fine on the 2.5 low-compression NAs. I run it in my car without any difficulty.

Yummybud924

thanks, I'll use just regular from now on. Regular is already pretty damn expensive. I thought that it may run better with premium.

GodSpeed

i run 91 but its chipped

89AZ944

Yummy-

It will depend on the model year. Check your owner's manual, it will be specific on which octane you should use. Like uber and witt habe noted above, the later models take higher octane. I ran 87 in my car ONCE. It was enough.

89AZ944

inactiveuser92616

cheap is best. Higher octane gas just burns slower if you dont need the anti-knock properties.

bader$

I run 91 except during the coldest winter months (better cold starts). I have an S with a chip.

WizPorsche944

91 here

I love porsche

93 here, with the extra bump in the CR of the 88 924S, i figure to play it safe and go with what the PO had put in the car as well