I would say try the new enclosure before you get the amp. I've heard 2-L7's off 300w each in a nice ported enclosure and they get pretty loud for the power. You can always upgrade the amp later.....after you make sure your electrical is capable of handling your amp choice. Of course all the advice given is just a guess considering we don't know the vehicle type, electrical, amount of space you have to work with, or goals.