Hi, i have a Audi a3 Cab and i am in the process of upgrading the sound system from a non bose Chorus two speaker to a amped 4 speaker set up. at the moment i have front and rear speakers all working from the new HU however i am now going to fit a 4 channel amp ,i have found a location for running the power and remote cable via the firewall and that is underneath the wiper scuttle passenger side looking at the engine ,grommet is out ready for feeding cable..The issue i believe i have is the drivers side for running the RCA cables ,i say that as when i ran the rear right speaker cable i struggled finding a route through to the HU i did manage via a small gap with a piece of wire to drag the wire up and that took a bit of time with quite a few attempts , so i know i will not have enough room to do that again with two rca cables and was wondering if anyone knows of a way of doing it by removing a panel etc , i can't see much apart from removing the fuse cover any help would be appreciated .Thanks