Personally I like the 78-88 Monte Carlo (all g-body cutless, gran prix etc.) clip better than the camaro or firebird due to the track width is not as wide as the camaro and firebirds (check out Kid's build I believe he used a grand prix).
Here are links to his threads
http://67-72chevytrucks.com/vboard/s...d.php?t=154951
http://67-72chevytrucks.com/vboard/s...d.php?t=219902
Both the camaro and the g-body clip ride nice I just like the fit of the Monte Carlo (g-body) a little better if I was going the clip route.
Also the early novas fit nice I recently had to repair a botched job on one. Here is a pic of the 70 Nova clip.
I did not go in to aftermarket kits because it seems you are leaning towards doing a clip. So I tried to stick to the question that was asked but like others said they are easier to install and work great if you decide to go that route.