Hi people, was first in the wrong forum…: There are already some threads to the basic topic here, but I’m looking for some more special experience with upgrading a golf 4 based on the navi-mfd (built in 2003, scissor speaker front and rear, no bose system) I want to sacrifice the trunk for a bass box, probably double bass reflex or double closed, in combination with digital power amplifier so 500-800 rms, 2 fiberd condensator, 50 mm2 cables from the battery now my problem is to design the front pair of speakers in this way (behind a few are left out, will be overdone anyway), that with minimal cable installation effort a listening experience is created that resists the bass pressure! Does anyone have experience with a similar set-up from the bass? as far as I know, the standard speakers are driven with the Navi integrated, low-browsing end stages (which is why where Hl the sciss navi cds always so hot). my main question is now how thick and how loadable are the already installed cables and there are any end stages that can process the already reinforced signal of the Navi as input, but at the same time offer the possibility to pass the new output power to the already existing cables ? How is all this done with the Bose sound system ? my dream would be if I could just switch between such a Bose end stage and d then only the loudspeakers (in the door and in the A-pillar) would have to replace. maybe I will also dam the doors, let’s see.