Is GSX L2 compatible with Win7 ?
If you already have the latest GSX installed, GSX L2 should run as well.
However, Windows 7 is not officially supported anymore by us, since is not supported by Microsoft anymore, since this January. Of course, there's a Trial, so you can check it yourself before purchase ( but if already have the latest GSX installed, you already have Level 2, in Trial ) but what unsupported really means is that, if you have a problem with it that might be related to Windows 7, there's not much we can do about it, since we don't test in Windows 7 anymore.
This also means, even if it works now ( so you buy it because you found it works now), we cannot guaranteed it will always work in the future.