A grounding mod is the next thing you should do after a resistor mod. In other words, it's rice sold on eBay to give the sense of knowing your Civic has now been transformed into a Porsche.
Seriously, some cars may benefit from a better engine-to-chassis grounding strap. If your engine is properly grounded (as is the case with 99.999% of cars) this mod is worthless. If you suspect your engine-to-chassis ground strap is damaged, replace it with 10 AWG wire or a similar braided wire strap.