The Larsen product isn't ABS, neither is the old RABS system. The RABS system was only to keep unloaded trucks from swapping ends and didn't work very well beyond that. You could, and would lock the front brakes during hard stops. There was an "anti-skid" device being marketed that was mounted inline @ the master cylinder some years ago. It made all sorts of claims about damping pressure surges and reducing stopping distances. It. Failed. All. Tests. and was taken (forced) off the market. Effective anti-lock systems are costly and complicated, and respond to changes in traction 20X per second at each corner independently. a non-feedback system can't respond to the changes in traction. Slowing down the application of the rear brakes when it isn't needed for lock up control is going to add additional load on the front brakes. It may give some benefit to a race car, but I'd need to see independent testing for proof. So if you are so inclined, spend the coin and do some before and after testing.