Nice looking ride, Diablo.........I haven't had the pleasure of owning one of the latter generation F-bodies, but have owned 8 of the 2nd generation and one of the 3rd generation cars.
I agree, the LS engined cars (and trucks) are pretty awesome. My current vehicle, a 2002 HD2500 4x4, has the 6.0L engine, and if things work out the way I plan, I will be adding an STS turbo kit to it in the spring, along with some other engine mods, like better heads, change the cam, etc, and beef up the 4L80E to handle the added power. Gonna be pulling the Vortec 350 out of my son's 1985 GMC Sierra and this winter and swapping in a complete 5.3L and related EFI setup, using MegaSquirt (just have to borrow a laptop for the tuning) so he will be kinda sorta modern when he gets his license.
Dunno what to think about the mileage discrepancy you posted above. Now I would be suspecting fraud and be very very leery of the car. Might do some more digging before you lay out the cash or sign anything obligating you to the car.
Just my thoughts....................