what's the best way to mount a sub box to the trunk

What I usaully do is go buy a large piece of very thin ply wood and paint it or carpet it and use it as a false floor so you can just get brackets or screw the box right to the board.

if your worried about some stealing it you shouldnt 9 times of 10 thieves wont bother with subs cause of the weight of the box. know if its just to keep it from moving around I suggest a couple of L-brackets.

if your worried about some stealing it you shouldnt 9 times of 10 thieves wont bother with subs cause of the weight of the box. know if its just to keep it from moving around I suggest a couple of L-brackets.

You sure about that on theives?

I spent 5 months in prison for breaking into cars and getting subs.

And I tell you, L brackets and the weight isnt an issue at times.

Not bragging, But just stating the facts from first hand.