GS Motorsports vs Superchips

I'm sure the programming is different (developed by different shops) but the main difference is you own the Superchips programmer (install programming yourself, updatable from the internet) and GSM will have get your computer or car to make the changes.

has anybody tried the GS Motorsports air intake system and their supercharger

There has been some testing and interesting results of the GS intake system and others by another Magnun Enthusiast Group which you can find online. The supercharger also has a history you can read up on. I can't post where here, but you should be able to find it in your LX search.