Sounds like you found a 99 GC limited.
I don't think i've ever seen a laredo with a V8 and quadradrive.
Oops. never mind, you said quadraTRAC - not drive.
However I don't think you can assume it's a V8 just because it has quadratrac.
I think any of the transfer systems are available with any of the engines, though some kind of 4x4 system is usually standard on a v8 (not the other way round).
Do you know if it's quadratrac 1 or 2? I think 1 doesnt have a low drive stepping.
look at the jeep website for more info on the different 4x4 systems.
They have a pretty good section describing all the drive systems and what they're suitable for.
I'd imagine you'd want to have a v8 if you intend on towing frequenty, I have a I6 on mine, but I've never halled any significant weight so I wouldn't be able to comment on its towing performance.