The larger the enclosure, the deeper it will play and the less power you will need. For the IDQ, shoot for a box with closer to 1cu ft. Like this one. Add 1 lbs pollyfill and shazam.
At .5cuft, the IDQ has an f3 of 62.5hz and QTC of .94
At 1cuft the f3 is 47.8hz and QTC drops to .72
Much closer to the ideal QTC of .707
On the amp, do you mean the Rockford Fosgate prime 500? It is a nice amp, but you won't get a warranty unless you buy from an authorized retailer. The Pioneer I liked at walmart will, and has more power should you need it one day. Also, you'll need another fuse to install the Rockford Fosgate beyond what comes in a typical amplifier kit.
Oh, and yes, dvc 2 ohm for a one ohm amp.
Well I didn't think this would be a ct sounds thread, but since they are having a sale... If I had 1k:
Headunit: (Kenwood Excelon KDC X701)[https://www.crutchfield.com/p_113KDCX701/Kenwood-Excelon-KDC-X701.html?tp=5684] 6ch, bluetooth for $180
Speakers: CTMeso $75/200 (sale)
Subwoofer: CT10 $50/100 (sale)
Amps: CT4ch $200/300(sale)
CT900 $219
Box: Amazon $50
My favorite audio wire supplier: KnuKonceptz I usually spend about $150 an order, but I get some serious gauge wire for my amps, you will probably spend less.
If you get it on sale it will total $924.
The amps you will never grow out of. Unless you start doing competitions. The subwoofer is the weakest part of the system, but seemingly the least important to you. That being said it is not a weak subwoofer compared to others, ESPECIALLY at that price.
I guarantee If you bought the above setup it would blow your mind. All you need to do is buy another set of midrange drivers for the rear doors at some point if you wanted to. There is honestly debate as to wether the rear speakers are necessary.
You are probably now like who tf is CTSounds. They are a competition grade company. Meaning the "entry level" stuff I listed is still leaps and bounds over consumer grade stuff. (think alpine, kicker, rockford etc.) And it blows it out of the water on pricing. Like jesus.