[mrnickleye]

I already know what I believe to be 'true' in the engine world, but you must decide for yourself. You have shown great intelligence and for-thought by asking questions, and not just doing stuff first.

I have seen far too many people do things to their car, (with good intentions of course), but ruin it.

I suggest you do further research on the net for more input.

(#5 needs input, Stephanie, be fore a Short Circuit)

I use STP because it leaves a VERY Slippery coating on the metal surfaces. The most wear caused in an engine is at a cold start. Hot motor oil drains back into the oil pan after sitting for a couple hours. It takes a few moments for the oil to be spread throughout the motor after starting.

On motors with more than 100k miles, leaks and seepage are normal. Parts clearances widen. So I use 20w-50 oil to help slow leaks, and fill the clearances.