I have dd amps and subs in my car and they are fantastic. The woofers weight 28kg's each. DD hold 5-8 world records with there subs. take a look at www.ddaudio.com.au

Here is a sig from another site.
Car 97 Civic sedan (with 2x 100ah Deep cycle battery)
Source Eclipse 8443
High 4x Peerless 1" tweets 811435
Mid 4x Peerless 6.5" mids 850467
Low 2x Peerless 8" woofers 850136
Full Range Amp Visonik V4218
Subs 2x DD 9515 's (when they get here)
Sub Amps 4x DD m1's