I dont see any gain in anything... I made my own grounding kit... isnt very hard... took a battery terminal that has a 2 4 gauge and 2 8 gauge connections... ran 1 4g to the body, 1 4g to the transmission and an 8g to the engine block.

Theres no way it can increace power and torque... mileage I could see a very, very slight improvement, as some sensors may work better... but I dont notice a thing in my car.