If you want to use both versions online, then you have a few options. You can copy the SFC3 folder, place it right next to the original, or anywhere else that you like, and rename it (GAW for example). Then you could do it the easy way, by going in to the newly-named GAW folder, finding the SFC3.exe file there (it looks just like the icon that your original install put on your desktop), right-click it, select "Send To", then select "Desktop (Create Shortcut)" and left-click that. This would put another SFC3 shortcut on your desktop, with a name like "Shortcut to SFC3". To avoid confusion, just rename that icon to GAW, and you are done. Just launch the appropriate file by clicking on its shortcut and have fun.
There is also the Server Profile Manager, which I use to switch between multiple modded and unmodded versions. The bonus, It saves several hundred MB of hard drive space per install. The drawback, it takes a few minutes to create a new mod profile, and to switch between profiles. Those drawbacks are greater the lower your processor speed, and amount of RAM on your computer.
If you want to download the Server Profile Manager, developed by the Temporal Alliance Group, I believe that The kind folks at
Battleclinic still have it up for download.