well sometimes u have to get creative...just find paneling that easily comes off and tuck it under...and then put the paneling back on(u don't want to go too far out of yur way like from one side of the car to the other)...then if their are any holes through the firewall just put a gromet in their or something to make sure that the metal won't work its way through the rubber insulation on yur wire and create a short...if you don't see a hole big enough...just take it to someone who knows what they are doing(which is what i did)...and ask them to drill a hole trough...then its easy... find a safe way through yur engine block and connect it to yur battery...i don't know what the interior of yur impala looks like but its rather simple...you could probly figure it out...hope it helps...