in reality any of the above mentioned ways will work jus fine.....me personally i prefer the side rails cause it is much easier for me to jus remove a few pices of my vehicle and then be doen w/ it...as for the guy stating running it under the car is good.....i'donly do that if i also ran some pvc pipe or something for the wire to run through as to prevent any damage from occuring to the wire from either bottoming out, dirt, rocks, or various other debree(sp?) that might come in contact w/ the wire and cause damage....