im not sure what to get 2 t215d4 from rockford fosgate or 2 n215

You need to provide much more information to help reach your goal.

Dude would you stop making this vs this, you have made like 5 to 6 of these threads and you get the same response in each one lol. RF shouldnt even be compared to a Fi sub, you would be paying twice as much for a RF sub so why should it be such a big deal, Fi all the way