If you're talking about a hyper ground kit (multiple ground wires running in a daisy chain) I doubt you'll see much of anything. With some cars I've seen people mention that their headlights no longer dim when the stereo is cranked up - though that doesn't seem the proper fix to me, but whatever - and I know a lot of people have made their own from 4 ga wire and gold terminals. In fact, I did this on my PT a few years ago and saw absolutely no difference, even though plenty of guys on various PT forums said it made a huge difference. Since I spent a whopping $10 on parts from a local car audio shop, and had a bunch of material left over, I wanted to see what such a system would to on our 1992 Chevy Camaro. Nothing. Nada. Zip. Zilch. The big goose egg.

Don't waste your time or money. Especially if you're looking for a horsepower gain out of it.