I like the first one better, Tim. One thing I learned with the GTO is that you want to be able to explain your tag quickly in those cases when you choose to explain it. When I got my '04 Goat, I got the tag "LS1GTO" (I was a regular on ls1gto.com, you see) but grew tired of explaining when people started guessing. ("Loves one GTO?", "Lisa's GTO?"

, whatever.)
I then switched to "GOTGOAT?" Muuuuuch better.

I still had to explain but the explanation was easier because people got the "got milk?" reference pretty quickly, and a surprising number of people would respond by saying they didn't know the GTO was back when I explained the "Goat" part...
Here's what I'm planning for the new Camaro (unless someone snags it first and assuming it passes review.) NC's online rendering left-justifies but the tags are really centered.