If it's in good shape you should go for it. The 98 had perimeter bolts on the valve covers instead of center bolts, a different computer, but it had a larger cam then the 2000 and up, and it has the 28 lb injectors. Lots of folks go with the 98's. Like the previous post mentioned, adding the LS6 intake would even things out (250 - 350 bucks).
Oh yea, the exhaust manifolds were a little different on the 98's also.
Dale
P.S. if you can do a compression check it sould be in the 175 PSI ballpark.