This is the perfect sub set up for under the back seat of a pick up or a hatch back this setup will not disappoint. 4x 2308d2 with 1500 watt Audio Dynamics amplifier. 
sub specs-

2308 sub

• 150W – 400W optimal power range
• 2″ voice coil diameter
• Designed for use in small vented enclosures.
• Engineered in the USA.
  

  Fs	47.10 Hz
  Qms	7.49
  Vas	5.47 l
  Cms	0.090 mm/N
  Mms	118.50 g
  Rms	4.72 kg/s
  Dia	159.99 mm
  Sd	201.08 cm²
  	
  Qes	0.54
  Re	4.11 Ω
  Le	1.63 mH
  Z	4.00 Ω
  Bl	16.20 Tm
  Bl²/Re	63.80 N²/W
  
  Qts	0.51
  no	0.10 %
  SPL	82.15 dB
  EBP	85.69
  
  Nominal Diameter		8 in
  Overall Diameter		8.39 in / 213 mm
  Mounting Hole Diameter		7.13 in / 181 mm
  Bolt Hole Circle Diameter
  Motor Outer Diameter            5.70 in / 145 mm
  Mounting Depth			4.92 in / 125 mm
  Required Pole Vent Clearance
  Driver Displacement		0.048 cu ft / 1.37 l
  
  Minimum Sealed Volume		N/A
  Minimum Vented Volume		0.42 cu ft / 12 l net*
  

Amp spec- 

X1.5k

• 1,500 Watt Class D Mono Block
• Upgraded with Larger Package MOS-FETS for Increased Avalanche Current
• Upgraded with Lower ESR Capacitors
• Linkable Master / Slave Configurable
• Dual MOS-FET PWM power supply
• Click-in-Place Crossover Controls
• Subsonic and Low Pass Filters
• Tiffany Style RCA Connectors
• Low or High Level RCA Inputs
• Auto turn on (DC or signal sense)
• Remote Bass Control w/ Clip Indicator
• Damping Factor >150
• 80dB Signal to Noise Ratio
• Reversible Top Plate
• 4 AWG Power Terminals
• Engineered in U.S.A. and Korea