i love DD.go with the DD3515´s.
1500-2000 each for daily is OK.
build the box after DD specs. do NOT tune them much lower than 40Hz. i know what i am taking about, i tried several boxes on a 9915, 9515, 9512 with different airspace and tuning frequencies. all sounded louder, cleaner, more punchy with 40Hz tuning than 34 or 36. yes, even the low notes hit a LOT better with 40Hz. DD subs are not human and do not even try to simulate with a box calculating program. in car it wont work with them.
give them each 3 to 3.5 cubes net volume and a port 15-16 inch long, area matched to 40Hz tuning.
DiDan
