you guys gotta understand what a TB spacer does, if your car is TBI than it will help because its actually giving the fuel and air more room to atomize, but if its a multi port car than it wont do anything because your intake is dry meaning the fuel is injected after the throttle body so it makes absolutely no difference. TBI means throttle body injection meaning the fuel is injected at the throttle body sorta like a carb if you can think of it like that incase you didn't know...
Hey, Kawasaki400racer, you're completely wrong. Not busting on you but you are off base on this one.
A TB spacer works on the same principal as any phelonic spacer. It increases runner length, and therefore some velocity to the intake and, depending on the placement, material and size, can cool the air charge a few degrees. Same theory as a GT40 or Trick Flow type intake on a sb ford motor. The Chevy is no different. In fact, many companies make a phelonic spacer that goes between the upper and lower intakes on split designs. (And yeah, these are all {as kawasaki400racer says} "dry" intakes).
I used to run a 1 3/4" phelonic spacer on several split sb ford intakes, including a GT40, Cobra, Trick Flow and PBF Breadbox. Definitely changed the attitude of the throttle response depending on what I was doing at the time with the motors. The spacer I ran came from Wilson Manifolds and were made of a carbon fiber/poly material that was machined for the specific type of intake. MPS in Georgia used to carry them for the Ford crowd. I am not sure about your particular application though.
Changes are, you will see absolutely zero change in mileage or hp on a stock v6 car though and you're better off saving your money for something else.
With respect to your EGR, be careful there too. Depending on the Fuel Injection system, the EGR can be an integral part. Kawasaki400racer is right in that you can definitely tune around it. However, an EGR is like any other sensor point in a fuel injection system. Keep it as a monitoring point but do away with the function for any other purpose. Simply removing it without making sure you've handled the contingencies isn't suggested.