i was loosing around 900-1100 rpms between shifts, specially uphill, with the change of sparkplugs to iridium it reduced to 500 rpms between shifts

and i've been testing different octanes for a while now, and 91 octane gives me 330 on a full tank, roughly 10 gal. 87 gas gives me about 280 mi. ( i always reset my trip meter after i pump, i put about 450 mi on my RS weekly. so i have alot of room to test and retest with differnt octane as well as gastations.

I'm in San Diego CA, sea level 70's F all yr around, i dont know if how much it plays into the equation, but thanks alot for your input, ill keep it in mind next tune up.