15": Kicker CVX or Sundown Z

I will be using one of these subs as a temporary sub setup till I get my electrical right, money right and subwoofer choices down to run my Sundown SAZ-2000D @ 1ohm. I have a 2003 Saturn Ion, stock alternator and stock battery so far and just took out my 3-12" Kicker CVX's in 5.9ft^3 @ 25.94Hz. As you can tell I love the lows (my priority in any system I have), I listen to: a lot of chopped and screwed music plus r&b, rap and old school. I will be building a new enclosure anywhere from 3-3.75ft^3 for the Kicker CVX 15" and 3.25ft^3 for the Sundown Z15. The price difference is $50 (Sundown more pricey), Im not worried about customer service (dont plan on blowing neither one and if so that will be upgrade time. I know there are other subs out there that you would recommend, or that you would deal with but thats not what this topic is about; its about these two exact subs I have listed already. I will get both subs in D4ohms and wire it to the Sundown SAZ-2000d at 2ohms, the box will be tuned to 28Hz (Sundown Z15 recommends a tuning of 30--35Hz only so that is already a downer but nothing to throw it out). The Fs of the Kicker CVX is 21.5Hz and the Sundown Z15 is 28.59, which sub will yield me better lows (only concern right now) tuned to 28Hz?

Thanks for the input and time put into this topic (Im already leaning towards the Kicker CVX 15" but curious to what the SSA members have to say). Im biased towards Kicker CVX subwoofers (I've had 3 different 12" setups from 1-12" CVX t0 2-12" CVX's on up to 3-12"CVX's and love the lows they put out).