Ok so I have now got a design for 2 DD 9518's. I have people telling me the woofers will have a hard time being that they will kind of choked would you say? Well anyway the design is for daily and SPL. It is tuned to 37hz, has 12.5 cubes and 205 square inches of port area. This will go in a 1998 corolla. How do you think this design would be for them? ***Below is the design.