i just sold my 98 ls1. had 95k miles. beautiful car. as for the 98/99 cars the only major problems most had were the window motors and wiring issues in the doors. the lt1's were the cars with the oil pump problems. the only difference between the years is the intake/egr/pcv designs. ive never heard of anyone having a problem with an ls1. vinnies car is nice too. has like 180k miles on it.
http://www.njfboa.org/forums/showthread.php?t=40586
link to the ls1 i sold for 5k