That's quoted right from my owners manual, you could easily play with the numbers to get it down to 13", I'd not trade my Kenwood for a Polk, it sounds great, and can hit as hard as any sub i have owned, or heard.
One last think why do you think the Polk will sound better?
oh, you have that exact sub?
well alot of people say "slim mount" subs don't hit/sound as well. idk if it's true, but i knew they knew alot more about stuff than me, so i believed it.
if you think i will be super happy with the kenwood, especially since the price is RIGHTTTT, then i will get it. last time i was sketchy about someone suggesting a speaker, i got it, and was very impressed.
leaving for greece on the 29th of may, wanted to get everything ordered so it's all ready for me to work on, possibly before i go a bit, or right when i get back!
i believe the kenwood is a SVC, so should i look for a mono amp? don't think my dash speakers can take an amp, because they are like 20w rms anyway, and i don't have any other speakers (will be tearing out the stock rears, possibly keeping the boxes though)