It is a major pain in the !Removed! to get the power wire in the car and then in the trunk after.
Pay someone else to do it unless you have lots of time.
I had to jack up the car , fish the wire through the fender and inside the support frame just to get it into the car without drilling. I found one grommet but it is no where near easy to access in the drivers fender.
BTW how much did you spend on the sub and amp?
Are you using the H.O. box for the w7 or the pro wedge?