I don't have anywhere near enough depth for those, haha.. I forgot to mention I've got like 4 to 4.5" of mounting depth.
I have a pair of Sundown SD-3 8 D4’s for sale in the Classifieds. Depth is 4.75” and pole piece is solid, so the rear of the subs can go directly against the back of the box. The surround is also inverted, so you only need about an inch in front of the sub to clear its 2” peak to peak excursion.
Kenwood DDX9903S, Arc PS-8 w/PSC, Arc Audio 1200.6, Helix SPXL1000, Audiofrog GB12D4(2) IB, GB60, GB25, GB10
I used a pair of the CT sounds BIO 2ohm subs for my recent build. only 150w rms, but I am actually driving them with the factory amplifier so the low wattage was preferable. I got two of them for right $100 so definitely budget friendly. Looking at their website, the next up in the line also look like a good deal, the Tropo 8 inch is 400w rms for around $80 a piece.
I have been super satisfied having just taken a random chance on them. Much louder than the single 6.5 they replaced, and still provides a very high end, full sound for the price.
Breaking shit since 1994
I ended up going with the NVX 8a, sold by Walmart so if I don't like them they can go back.
I haven't gotten them fully installed yet, but they seem satisfactory right now.