i would go for in-cabin pare. aside from being safer and less hassle. it will be cheaper din because you don't have to get a huge amp that the s12L7 requires.

i would even recommend a pair of round subs, maybe a pair of 10 inch comp VRs (if you want kicker talaga). i like the sound of the roud subs better than the square ones kasi (personal opinion lang ito)

andy