I'd need to remove some panels from your car, remove the existing sub, check out the wiring pin outs, take a lot of photo's, do some measurements and see if either the current 8L box could be made to fit or if it needs to be a new design. I'd then put it all back together and may need to do all again once the new design was ready.
So it's not a quick and easy job and fully understand any apprehension at having someone using your baby as a guinea pig. On the upside I'd do it all for free and you could have the resulting system for the cost of the amp & the sub.