If your going to be out on the highway, crank the air pressure near max. The tire will wear better, and you'll have less of a 'contact patch' thus less resistance, better milage (true only by like .5 MPG er so..) but still better. I run mine at like 32 Lbs all around. If the max pressure is like say 45 PSi on the tire sidewall, I'd run like ~40.47SLTDuRide said:
Royal Purple is expensive. I can't say that it's any better than any other synth for any reason. I've heard that to be called a 'synth oil' you only have to have a certian percentage (like 60%) synth! Royal Purple (Unlike Mobil 1) is 100% syn. I run mine for around 6K. Filter too. Never had any problems. I also get it at 10% over cost (thanks to Napa) so it's only like $3.40 a quart.