I own a tundra QC and I only use 1- 12" JL Audio sub that is ported using a PPI amp. Its plenty for me but not sure what you are expecting out of the subs. Also I owned those pancake subs (slim) from kenwood and kicker and it just was too boomy 2-tone frequency subs for me and it lacked accuracy.
HT: PJ: ?? , Screen: ??,B&W 684s, 685s, HTM62 / DIY SI 18" / port tuned- 17hz
Onkyo 809, iNuke DSP1000, Oppo 103 , PS4, HTPC- Lenovo q190.
| Media Room: Yamaha RX-A 820, PS3, Vizio 55 (M-Series) with in-wall Polk Audio RC series (5-channel), Sub1200 (dual) w/ DirectTV & PS3 / PLEX | Family Room: LED: Sharp 70" -Smart, DTV Client, PS3, Mirage MX 5.1 / HK Audio.