Typically, and forgive my directness, but my experience has shown that one or the following is true regarding Pontiac engines. 1. The person working on it has no idea what their doing...or 2. See #1.

All engines are air pumps motivated by a combustible material. Whether Ford, Dodge, Chevy or BMW, the principle is the same. The nuance or "expertise" comes from a dedicated builder as Butler taking the whole bastard child engine on all at once.

A Pontiac engine is different than most others as they changed their head chamber size rather than changing the volume of a piston to raise or lower compression. Taking a Pontiac to a Chevy or a Ford guy who knows nothing of this and how a Pontiac gains it's torque and HP 800-1500 RPM lower than a high revving chevy is just opening up bad stuff.

That being said...I encourage whomever reads this to research Pontiac specific material and spend their time (and money) wisely by seeking a builder/tuner recommended by someone. Not all engine builders and tuners are the same....the principle is.

Pontiac's don't like single plane intakes and big cams such as your RAIV unless you have the gearing AND compression. They also like tight tolerances and tight assembly (minimal vacuum loss) Pontiacs also LOVE demand orientated carbs such as the Q Jet over a double pumper Holley. Perhaps I am biased here...but I've never had luck dialing in a Holley nor have many who have tinkered with, run and written about the various effects of head, cam, carb and exhaust (Jim Hand)

That said...its your investment...I'm a purist. You will see better fuel economy and reliability with your choice with the WS6 engine. Don't forget about the piston slap, wrist pin and lifter issues with the LS1. I know...owned an 02 WS6. Common problem.