I have a 2001 quad cab 4x4 ram. i bought 2 polk dx10's both 4 ohms. i look every where for a box and came across a mtx thunderform. The subs fit perfectly but its 1.75 cu. ft of air space. i sold my mtx 500d cause i needed the cash so i'm running each sub bridged off a 400a4. i was supprised. it sounds damn good but is it to much air space?