I have a G4S here on Lima Peru, and talking with AFM ( a forum member with great tips and knowledge) here on Lima he have decided that the best combination will be to get a G4JS and put some parts of the G4S,
The RS is great for track with traction and very fast, on the other hand the flex of the chassis from the JS will help on low traction tracks.
G4 is a great car and TM have very good products,
have fun
ALG