I tried the Avid springs this past weekend and found that my buggy jumped way better but it did feel bouncier.
Overall I feel that the springs were a good investment.
I was using the orange/yellow Losi springs prior to switching.
I used Yellow rear, red front Avids.

Rears - ■Yellow: Rate: 1.99lb | Wire: 1.17mm | Coil: 12.50 | Length: 63mm | ID: 16.25mm

Fronts - ■Red: Rate: 3.28lb | Wire: 1.17mm | Coil: 7.75 | Length: 44mm | ID: 16.25mm

Front Oil - 35
Rear Oil - 30

This setup was for Norcal Hobbies - indoor.