I wouldn't bother with an expensive TB/manifold combo unless I had a huge heads/cam combo.
I'd spend the money and get the stock manifold ported. Its a terrible design stock and you will get a solid 20rwhp for cheap.
If you change the manifold, you will need a tune.
Also, don't forget you will need a clutch and likely suspension to 'use' the power from a cam.
2003 Corvette Z06 - MGW shifter, Corsa X pipe, Corsa Xtreme exhaust, Texas Speed long tubes w/o cats, PowerStop rotors/pads, Conti DWS tires, C6Z51 F&R sways, C5R headlights, tuned
04 GTO - sold