Originally Posted by GraphiteGhost

. If you use the 74mm TB/MAF, are you putting the MINIMUM 91 octane, or are you also saving $ by using 89? I suggest if you are, you may be seriously lean! OK, now please lets not jump on my assertions about my XF and 89 octane, lets find out who might be doing the mods and not using minimum 91 octane (before getting a tune). OK?