Jay, there are a few GSXR models out there. If your GSXR is older than 2004, almost all of the frames are identical in dimensions, so you can use the 1000 chassis anyway.
http://sketchup.google.com/3dwarehouse/details?mid=30157c4a6c09f884c97a3fcdcfe70d5&prevstart=0
I doubt there is an Agni model out there, but the shape is really simple and you should be able to fit it in with ease.