I got a 93 740il, i want to mount the subs on the rear deck and do a blow threw... dimensions of the trunk are - width 3', height 1.5', and there is a difference of 6.5" from top depth to bottom depth being the top is less, the port thru the rear seat can be a max height of 1.5' and is set at 1.1' without cutting any leather seat and width of 10", i have allot of room to play with the depth in the trunk well over 3' in the least deep spot, i tried using re's box calculator but it didn't help that much. thanks.

What exactly is your question?

o shit sorry, for got to ask.... is there a good program out there to help me with this?

Help you with what? 

 

Designing the enclosure?  Calculating how much space you have available? 

Design the enclosure, and do u recommend mounting them like that, or is it gonna cause problem with my rear windshield, i was also thinking about getting a N315 or 18 instead of the 2 bl's and doing somthing like a w7 high output box still going thru the rear seat, what would hit harder the 2 bls or some type of set up with the n3? thanks

You shouldn't try to fire your subs forward unless your seats fold down. There are many steps to take, but you are not providing enough information for us to help you much. The rear window will be fine. I have a forward fired trunk wall in my SRT-4.

what info do you need? and why not mount forward, i could mount the single 12' N3 inside that rear arm rest with the port below or on top or both? but heres what i have to install so far a set of Hertz hi-energy HSK 165 XL, a set of JBL P660C, Kappa four, 2 Kinetik HC1800, 240 amp alt, Crescendo BC3500D, Alpine DVA-9860, 2 gauge for the kappa, 0 gauge for everything else and 4 gauge for the sub wire lol because thats all they had left and gave it to me for the price for 8 gauge (over kill?)... in the future im putting the kappa four in my girls car with the jbl's and getting a rockford 4 channel and another set of hertz because after hearing them i fell in love, my friend keeps telling me to scrap having any components in the rear and mount both sets of components in the front, how would that sound having to different sets side by side?...  I don't not have enough room on the rear deck to mount anything bigger than a 12" or a pair and do not want to have the sub in the trunk, i also do not want to lose the rear seat, so my question is what would be the best application for my car for a daily driver set up to listen to hip hop on with either 1 12" N3 or 2 12" BL's and witch would hit harder running off the BC3500D, i know the BL's will have more surface area to move air but can i pushing them as hard or harder than the N3, and also is my 240 amp alt good enough or should sell it and try to hook 2 200 amp alts up witch seems like it would be a nightmare because there is next to no space under that hood

one more thing... in the 740 the batt is located under the rear seat with stock low quality 0 gauge running to it after i install the high out put alt, do i need to replace the wire with high quality 0 gauge or run to wires from the alt because it is traveling so far, thanks.