This came out of the r1cer community. I'd like to see ANY scientific evidence (not Tornado-style 'bench evidence') that this does absolutely anything except lightening your wallet.
Bad grounds can have a severe impact on the performance of the car's stereo and it could do things like make the GM go wacko in a BMW (we've seen that) but how does it affect gas mileage?
2001 325i Touring Alpinweiss/Anthracite cloth, Alpina Softline
1988 M6 Royalblau/Silbergrau Nappa