How loud they can get? All depends on placement of subs, sub box size, vehicle, Setup, Hz, Deck, amp , wiring. they all affect the performance of the subs. L7's are ok. Personally i dont like em. Ive seen over 20 get blown. If you are stuck on em get a matching kicker amp. Why not keep 1 brand.
kevin if you want good 50 hz punch and some really good low end do 3.00 cf net each sub and tune the port to 34 hz if you want a good punch around 55 hz and better upper end bass do 2.00 cf. net each sub and port to 34 hz
i see your interest in the l7 and thought i'd give some personal experience on them. i had 2 in a ported box in the back of a 2 door tahoe. although they did have their moments i wasn't happy with the overall quality of the speaker. they would easily over heat and pop if pushed too hard. fortunatly they were stolen and i was enlightened by the jl w7 line of subwoofers. if it were me i'd run 2 8s or 2 10s.
I might go with the tens but i have been reading some stuff about the L7s and from what i have picked up they are over rated.I mean yeah i know they do and will hit hard.Ive heard them.But they say that they mess up fast and they have more downs than ups Thanks yall