I dont know what kind of box I should use (sealed or ported) for two alpine 12" type-R. I heard that it matters what your back seat does, so my back seat folds down?
ported if you have space. They sound very nice in sealed enclosures as well. Its win win, up to you. I had a pair of 15's sealed in my yukon on a bx1500d and it was loud enough for me for two years. Then I wanted louder and thats why I have what I have now =).
I hear you get more SQ from a sealed one....But ported ones can sound just fine with SQ and get loud with spl, depends on sub....For the type R's i'd go with Ported 4 sho