The box can get kinda heavy when you're trying to get it in place while on your back. I've done it on two cars and one thing I did on the second car that helped was I got an extra bolt the same as one of the mounting bolts and cut the head off. I then used this as a locating dowel to get the box in place. I put the remaining two bolts in then switched the dowel for the last bolt. Made the install a whole lot easier IMO.