You need an oil with a low volatility index in a DI engine... Something like Pennzoil Ultra or Casterol EDGE... The oil is more stable which means much fewer particles get flashed off and become vapors which can be sucked into the intake manifold and coke up the valves.
Also since you aren't an engineer and don't know to what tolerances the engine was built on the bearing clearances, and with what viscosity they designed the AFM and VVT actuators to work I wouldn't go changing weights haphazardly....
