My friend tried to fix subwoofers into his car but they just wouldn't fit. How can a person get precise measurements when opting to fix the subwoofers into the back of a car?
I prefer to let someone (with the necessary experience) handle such tasks. I realize that I am not so good at some things so I prefer to delegate even if this is at an extra cost.
I guess your friend was doing this for the first time?
I've always opted to have the more experienced people handle those kind of things for me because the truth is that I uaually make a mess of things and it ends up costing me more to fix my mistakes than it would have if I had just hired someone to do it.
As much as we might like to believe otherwise, not all of us are good with our hands or at designing stuff like what you want to do, and it's nothing to be ashamed of. Just find a professional to do it for you and maybe you could watch and learn as they install the speakers in your trunk so that next time you know what to do.