octane booster are pretty much worthless, you put in a tank full of 89 with octane booster it'll probably be 89.3 or something now so its not worth it, so just be careful and don't go racing and fill up with 93....and like koala said just add premium when half tank so it'll even out to plus......

 

89 is "plus". And, as everyone says, it's no big deal.

 

^^^I guess 89 is plus where you at, in texas 87 is regular 91 is plus and 93 is premium =P

 

I guess so. 87, 89, 93 here.

 

The car will live. Sadly enough most dealers probably fills them with 87. I've seen much more finicky cars than the S2k get filled up with 87 at the dealer.

Just drive easy on the tank if your concerned and then hit 93 as soon as you can.

 

where i'm from there is only 1 station around with 91, I always put 93. Is that ok or do I really need 91?

 

bestbooster in US increases octane by 1.9 points.

 

In California, we only have 91 octane, so I just fill up with Chevron supreme.

 

91 is all you need anyway. The stock ECU can't do anything with octane higher than that. You're just throwing away your money by filling up with 93...

 

unless you can't get 91... 87, 89, 93 here