Best thing is to look at the codes in the trunk... 9C1= police package, G80= limited slip diff., As far as what to watch out for, well, make sure it's an LT1, the L99(4.3L v8, baby LT1) cannot be told appart besides using the VIN. or the stamping on the side of the block, unless u wana pull heads and compare bores!!!...lol
Read the "cheapa$$mods" on the forum...all you need to know to start. I'm sure someone has the VIN code for the LT1 handy, but I should know this...I suck!...lol
Remember, maintenance before upgrades, there are a couple of issues to address in the 9c1's and SS's before attacking them with mods!.