Fi Audio makes some solid subs that can handle a ton of power, an SSD is about $200-$250 depending on the options you pick, but it will get loud and stay clean.
https://ssl.perfora.net/www.ficaraud...iew.shopscript
The Q is a step up, the price reflects that, but after hearing one in a properly built sealed enclosure with about 1800W, I have to admit that I haven't heard a cleaner sounding sub get that loud in person since.
Then again I've also never heard the DC or the Sundown in person.
Not tryin to bag on you Kolton, Alpine is a very reputable brand that makes quality subwoofers, but after finding smaller companies like these^ I find it hard to justify the price tag of any Alpine, Rockford, Kicker, etc.
Stupid thing is that I still don't have money for my new build due to car repairs/upgrades and bills, so I actually own two Rockford P3's, the newer ones with the aluminum cone. They're loud and pretty accurate, but meh...