This may be a build log so no sense making multible threads. I am itching to do something different and go bigger. For those that dont know, I currently have a 15in Q on a SAZ1500v.2 in a box I designed and built that is a rear center console in my truck. It hammers the lows and the output is simply amazing for only one 15 here is my truck Here is the current full list Power and wiring Big 3 done and all 1/0 KNU OFC 2 Optima Red tops, gonna add a 3rd *Monster Cable... Slim battery terminals Stock alt (for now if it holds voltage up) *Tsunami main fuse holder up front and distribution fuse box for back. *Kicker ground block *KNU 10 gauge speaker wire for sub, 16 gauge for speakers RF rca's, etc Head Unit Alpine IVA-W200 NVE-N872A KCA-100BT Sub, box and amp *one 15in FI Q, cooling option and extra spider *3.65cu ported console box tuned to 29hz *Sundown SAZ 1500D v.2 Speakers and amp Rockford T-2652s Components up front Alpine Type R 5x7 rears Alpine PDX 4.150 (love this amp) Here is the current box 3.65 tuned at 29hz. Here is my current amp setup install and space to work with (maybe) Now here is what I am thinking so chime in with your suggestions as nothing is set in stone yet. Switching out the Q and buying a FI SP4 15 to go in my current box and either add another 1500v.2 or just buy a 3000d or something similar. I am not sure how much of an increase in output I will gain but the SP4 looks like it would work great with my current box and tuning. OR go big with alot of cone area. I have sorta been itching to take both rear seats out and doing two 18in SSD's in about 16 cu ft tuned to maybe 32 and running those both off of the 1500v.2. If down the road I want more output than that (I cant imagine so) I could just get a larger amp. I am not totally against other subs but I have been very impressed with my current FI so I dont hink I could go wrong there. Maybe some ICON 18's? If I do 18's I will add a second set of Components up front. Goals are low, loud, clear. Music is Rap and Rock