Alright so I have been searching around the forums for months now trying to build a system.

I have a Kenwood DDX-418 head unit and 2 pairs of bargain 6.5 coaxial speakers
I have KnuKoncepts 4 gauge OFC wire (can upgrade if needed)

I have a budget of about 650 for the sub/subs and amp

I was looking at the Alpine MRX-M110 for the amp, but I think there might be better out there for $275 (Alpines Amazon Price)

So I need suggestions on the amp

Then the subs I were looking at

-2 Alpine SWR-1223D
-2 Rockford Fosgate P3D2-12
-2 Image Dynamics IDQ12v3 D2
-1 Rockford Fosgate T1D4-12

And do I want a nice Cap or second battery
I plan on doing a big 3 upgrade as well

I drive a 98 Maxima so the trunk is fairly good sized
I plan on building a custom ported box

I am open to any and all suggestions