advice on building a box

I going to build a box for 2 Audiobahn  AW1508Q 15's What type of box will give me the best deep low bass. . (IE) Long, short, high, low, ported or sealed. If i mount the woofers backwords will it sound diffrent then if i mount them the normal way. ¾

I would do a ported. You can get good SQ and lots of low bass by building a ported box with a fairly flat response to match with the transfer function of your car. Ported is more efficient than sealed because the port uses the rear wave of the sub as well as the front to reinforce the output. Audiobahn has recommended specs on their website, though they have never impressed me and I will usually always use my own designs. I havent got to play with the '08 series, though I have been impressed to no end with the lower lines of Audiobahn.. Great subs.. You should not have a large output difference by inverting the subs, but for SQ purposes I probably would face them cones out because the pole vent on the rear can make noise as air enters and exits to cool the voice coil..

the loud speaker design cookbook, is another good but inexpensive  book