Are there two different GTO pumps, LS1 and LS2?
FWIW, I'm running a Pontiac G8 GT pump (per PO and builder BobH's recommendation) and I'm pretty happy with it. Seems to provide an appropriate amount of boost around town and at the track. Never feels overboosted, and no problems tracking it.
I *think* that pump should be the same as the LS2 GTO pump, but not sure...