I think ian c hit it. you want to avoid driving around at the variocam roll-over points to keep from having the flappers and cam knocking back and forth. cams actuate at 1500 and 5500 rpm, and resonance flappers at (I think) 4000 rpm.

regarding resonance, I don't think there is anything definitive on that which I have seen. pedro is a nice guy but not a mechanic so i'd take that with a grain of salt. I think the 3000 rpm thing most likely comes from the vibration that some folks experience at that rpm range. I get it in my car and, depending on what you read, have heard that it is due to exhaust resonance, failing dual-mass flywheel or failing motor mount. ie, some sort of overall vehicle vibration and not a driveline/bottom end issue that will result in the engine rattling itself to death. the dmf is there to address any potential engine harmonics and it's a whole other argument as to whether cars with lw flywheels have any excessive vibration/harmonic resonance issues (that result in broken cranks, etc.).

to southernstar, I would suggest that gentle braking is harder on your brakes than hard braking - more heat gets introduced into the system if you brake for a long time vs a short time.

personally, I do everything to keep the tach right of vertical at all times. mechanic tells me its the strongest 3.2 he's ever seen and oil filter consistently returns a clean bill of health.

Radium King, if late and hard braking reduces brake wear, why do cars that are tracked have to replace their pads and fluid more often? Theoretically, I suppose if you locked your brakes they would no longer generate any heat, but otherwise...

Brad

well, work = force x distance, so you can brake lightly over a long distance or hard over a short distance; same amount of work done in either case. note that brakes convert kinetic energy into heat, so high performance braking becomes all about heat management - the longer you are on your brakes the less opportunity they have to dissipate heat. I guess it only really matters in a racing environment, though.

some timely talk re low rpms and bore scoring:

http://986forum.com/forums/general-discussions/47812-3-8-replacement-motors.html#post358261

75% of my driving is on LA freeways with the cruise control set @ 73mph & 2900rpm.
After rebuilding my engine & balancing all recipricating parts & flywheel & pressure plate, I was amazed at how much smoother the engine feels & sounds. So much so that it seems tamer & a little boring. That was the 1st time I was motivated to buy a louder muffler.