its not the car.............IS vs IS

Hand-built engines IMO will tend to have more variances in performance since hand-built engines can't be as precise as machine-built machines......

And also, don't forget the type of gas, different brands of gas, different gas stations (gas been sitting too long in the tanks), your driving habits, (granny driving causes carbon build-up in engine), etc. ALL contribute to the overal performance of your vehicle .....Just to name a few...

Originally posted by mrclam:
it is good to go to redline once in a whlie because it clears out the carbon buildup in teh engine..

Click to expand...

Not necessarily to redline, but occassional higher-rev driving should do the trick......e.g. normal freeway driving for about 15 minutes should do it. If you drive on the freeway all the time, then there's nothing to worry about.

And it does help to clear out the carbon buildups.

Constant city driving at low RPMs will lower the engine performance because of the same reason.