good thread. nice to see u guys helping. somthing i want to tell u (maggie and geforce)
1) try to tune a woofer above its fs. because below the fs point , the woofer will unload itself (more prone to mechanical failure).
2) Winisd pro is not very accuate. i actually for got , u need a specfic amount of port area in a box to make it sound right. (i think it was 1" per somthing......) so if it says 3" wide x 3" long port for a 2 cubicfoot box , u know it is wrong....... therefore the above design is totally wrong! u cannot acheive anything from a 3" round port with 3" length excpet for some terrible port turbulance.
3) in trunk cars , the tuning is generally lower. means if u got to tune the box at 40 hz , in the car (trunk) it will go much lower about 37hz due to cabin gain.
4) in small cars where the trunk is the cabin itself , its better to tune it to higher
devil smil :-
try this.
36wide x 14 height x 16 deep.
this will give u about 4.7 cubic foot. and by my experiecne , u should have about 3.8 or 4 cubic foot after all displacments.
you vent will be 3" wide x 14" height x 28" long.
this will give u a fairly deep bass tuning and then if u dont like the way it sounds , i will start to cut the port down 4" to bring the tuning up. stop at around 17" since going smaller then tht would start to make things worse.
i dont have winisd on this pc so i cannot give u the exact measurments. but this is all from my head. sorry if it gets messed up 
