Nov 04, 2013 - 03:18 PM
I have used both units with my own RV and towed vehicle and they will both work in your Sonic. I would say the SMI is slightly better than the RVI unit due to its live pedal functionality. The real differences in the units are in the installation. If you plan on keeping the sonic for more than just a few years than the SMI Duo system would be the way to go. Since it is installed permanently one time, it is super convenient not having to deal with it while hooking or disconnecting the toad. The SMI system adds vaccum to your vehicles braking system to deliver a live brake pedal. This allows for a little better braking accuracy. I would recommend the SMI if your towing the Sonic with a smaller motorhome. The accuracy in braking becomes a little more important in motorhomes with less braking ability and weight behind them. Installation can be done by someone with limited mechanical ability and using standard tools. They have a step by step video which is super helpful.
The RVI is the way to go if you change vehicles often or just don’t want to deal with the more involved installation that the SMI requires. The RVI needs to be placed in the drivers floor pan area and the brake pedal cylinder bracket is easily attached to the brake pedal, power cord is plugged into the cigarette lighter (power port) and the brake away connector is plugged into the unit. You hit the start button and it cycles the unit and gets it ready for use. This unit does work off of a dead brake pedal since the vehicle is off and there is no vacuum in the system. So it is not quite as accurate as the SMI system, but is very effective when having to stop quickly.
I hope this helps, if you have any further questions please let me know.