I have had a couple different set ups, first for SQ, then SPL, now wanting to go back towards Sq. Sundown makes great woofers, the Nightshades are awesome speakers. I was running a Memphis MOJO 12 for a while and loved it. I currently have 2 Orion HCCA's. If you want to go for SPL check out the Fi BTL, DC Audio, DD Audio, and Ascendant Audio. They are smaller companies so you are paying for the product and not the name. Sundown has amazing amps so keep them in mind when you are in the market for an amp. I'm sure you know but you will need to beef up your power supply, depending on the woofer/amp you get. Look forward to seeing what you end up with!

Ascendantaudio.com
DC Audio - Subs & Amps
FI- https://ssl.perfora.net/www.ficaraud...iew.shopscript
DD Audio : True to the Source | DD Audio