Hello,
I just wired my subwoofer to Passat B8 (i took cables from trunk and connected High/low adapter Helix AAC.3)
Subwoofer : Kicker VL7R102
Amplifier : Kicker KXA800.1 (+ remote controller)
Capacitor : Hifonics HFC 2000
Cables : 50qmm
I connected all of these, but subwoofer is very quiet...