What do you mean by ground effects?
If you're trying to make it look like a 3rd-gen, I'm afraid nothing is available. All that is available is the Z/28 spoiler, your choice of 2 rear spoilers, and the IROC air dam if you can get JB to make you one.
You can also get A&A or Motion style door flairs, from www.showcars-bodyparts.com,
if you feel like being raped and have a whole lot of patience.