Unsure of the make of plug in harness for your car on my 2018 Mk2 I used a scosche plug loom - and just spliced in speaker out puts in replacement loom to avoid cutting cables - small amp is usually under front seat/central console for bose and passenger footwell for non bose - hope this helps - the jbl active sub is fused - but I ran new lead from battery and fused at battery connection to protect lead against shorts etc. between there and boot connection and earthed JBL under rear seat near boot - there are existing holes suitable for this and just a case of sanding/grinding off paint around them slightly for a good connection whilst keeping the wiring as short as possible - running positive from battery not too hard as the plastic trims inside doors etc are easily removed for a route and you can get into the boot by removing rear seat base - there is also a pre drilled hole with existing wiring into car from under hood behind and just below battery where there is just enough room to squeeze through and sheath with a cable pulling/threading 6mm rod - fiddly but if you take it steady easily achievable