hopefully getting a fi btl 18

I got someone coming to get my truck so hopefully in a couple days I will have a civic hatchback with tons of room for subs once I take the back seat out.  I'm planning on running my 2 Type R's on the JL 1000/1 and getting a Fi BTL 18.  So to start off what would be a good amp for this.  I'm guessing I'll be pushing close to 5,000 watts.  Also what power improvements will I have to make.  Bigger batt, alternator, and 0 gauge all the way back is where I'm starting but do I need more?  And can someone help me with some box specs.  On Fi's site there isn't even a spec for a sealed box so I guess a ported box is required.  I've never dealt with building a ported box and I don't know what kind of port or size.  I also don't know how to tune the box but I know it has something to do with the port.  I figure I could go ahead and get some info so I'm ready when I get the stuff.  Thanks in advance.

That's a lot of bass in a little car. I would stick to just the single 18 and push it with an Audioque AQ3500D1. I keep hearing great things about these amps and might just get one.

You can roughly figure 500amps needed to supply those amps. The Big3, 1/0 cables and very HO alternator will be a must. Not sure how big of an alternater you can get fitted in that civic but I would guess you will need some more batteries as well. That's a huge amount of power that is going to take some serious electrical foundation work. Not difficult to do just time consuming and a litle cash, those alternators arn't cheap neither are good agm batteries.

I heard the new 15" RE prototype behind 6000 watts in a civic hatchback a few weeks ago. It hit 146+ and the amp was starving for power. If you can get that much power to a proper enclosed 18 it should be pretty impressive. Good luck to you man.

Thanks for clearing that up.  Are there any drawbacks of going universal.  it doesn't cost anything to get it.  The audioques'  rms at 1000 instead of 2500 which is a pretty big difference.  Can these subs both handle more than what they're rated at or what? 

i have 2 audioque 2200d and 2 fi btl 18s going in a 16qf box tuned to 33hz... my ride is a 99 s10 blazer 2dr. on 22s.....  the fi"s are dual 1ohm i was going to wire the amps down to 0.5 and put around 3000 to each 18 but it my clip or somthing.... so strapping them is what im thinking about . how do u strap them? and how loud do u think it will be... p.s. 5 batt set up alt puts out 220 @ 2000 rpms and i did the big 3 wiring 0g wire