I'm not real partial to Kenwood subs, especially the tornados, i don't think they sound very good, but with 3 12s i think it should sound alright. Im not sure about what amp to push those, you should look at something like the new kenwood excelon amps, depending on your budget
With the type of car you have I see a lot of trunk rattle. You might want to look at insulating it a bit(I think insulating is the word I'm looking for). Just my 2 cents.
I suggest staying away from the tornados, they aren't one of kenwoods most reliable products. If money is a major concern, let us know what you can spend, and we can possibly point you in a better direction. You might be better off going with 2 subs, rather than 3.
Forgot to add: What are you looking for: SQ or SPL, little of both? Amp?
money is not an object i got a grand cherokee with top of the line stuff in it (8) 10'' mack daddy. im making my elantra turbo and putting a couple of goodies in the engine just wanted a nice little system.
So if you have top of the line in the cherokee, why were you gonna put the tornados in the elantra? Get some better subs. There are many great subs out there to choose from, might as well do it right. Why not stick a couple mac daddy's in the elantra? Or go with a couple Eclipse 10's.