amp and speaker choices?

Ok well heres the deal.  I had 2 rockford T1's Dual 4 ohm speakers 12" with a Hifonics XX Colossus Amp.  They got stolen last year in July.  About a year later i have money and realize i dont wanna do without them this summer.  So I liked Hifonics.  I ordered 2 Speakers from them they are called Brutus BX12D4.

Sensitivity is 93.39 dB
RMS 600w/ 1200w Max

Dual 4 Ohm

2 dual four ohm speakers mean i can run at 1 ohm if i am correct, right?  Anyone hear anything good about these speakers?  You know if they will compare to the rockford T1's? They dB of the Rockford T1's is 85.7 dB does that mean anything compared to 93.39?  Does that mean the other ones are louder?

Ok the amp im planning on getting is a Hifonics Brutus Bxi1606d which is a Super D-Class Amp that runs 1600 watts at 1 ohm.  All i would really need is the 1200w amp right?  I think i might just get the bigger one incase i decided to add or change anything in the future.  What do you guys suggest?

Now with the box.  It says you can run vented or closed.  I think vented would be better?  what about you guys?

heres the specs

Closed:

1 Cubic Ft. Per Speaker

then it says Fc (Hz): 51.7 whats that mean? do you have to change something since its for 2 speakers?

Vented:

1 Cubic Ft. Per Speaker

Port Size 3"x10" would you need to double it for 2 speakers?

Fb (Hz): 36.74

Fp (Hz): 39.81

What exactly do those last things mean?  Also can someone build me this box good quality for a descent price let me know? PM me

Why don't you cross-rate?  Weren't you a second class when I met you in Souda about 4 years ago?

I've never dealt with hifonics, so I can't give you my opinion.  Yes, you can connect them to the amp at 1 ohm if you like.  The difference in those sensitivity ratings may look substantial at first glance, but the hifonics rating is probably in car (which makes a big difference due to cabin gain).

The type of sound you are going for will play a big factor in the enclosure you use.  My guess is that you want knock-your-head-off loud, which would dictate a vented box.

I'll let the box gurus take it from here.

The sensitivity of a speaker doesn't tell you how "loud" it is. It is only stating how efficient the speaker is. (How well it makes use of the power you are giving it) Higher efficiency would obviously mean that it would take less wattage (or a smaller amplifier) to make it sound good. Just because a speaker has low efficiency doesn't make it a bad subwoofer. It just means that you need more power to make it sound nice. The Orion H2 series is a perfect example of this.

Hifonics is not a bad company at all. Stay away from their low-end stuff and you should be fine. They make very solid amplifiers as well as subwoofers.

The enclosure is really your preference as geepherder stated. It depends on what type of sound you are looking to get. Sealed enclosures usually take up far less room than vented. (You could get away with less than 1 cu. ft. per speaker) They also produce very controlled, "tight" bass. Vented is basically the opposite. Low bass, along with bigger dimensions. If you are looking for something louder, then I would suggest a nice sized vented enclosure. (1 to 1.5 cu. ft. per speaker)