Found this with google.
Rough Measurements 99-04 Trunks
3-1/2 Feet Wide with about 3-4 inch extra on side towards the ass end of the car...
15 Inches High clearing the stock speakers (my box is 15" high)
Back seat 11-1/4 Inches to slide thru without takeing the bracket off.
Trunk opening clears a 10 inch deep box
again these are rough u may be able to add a few inches to the width and trunk openening depending on what u do... the height is max tho!!!