Zirk,
Sorry my friend, didn`t intend to blast off at you there, frustration is kicking in over trying to reply in laymans terms to a problem that really isn`t important to 99.9% of the people, yet I`m waiting for the 0.1% who are going to argue no matter what I respond with.

However . . . . .
You have a cupboard full of DCA800 amps, some MB Quartz speakers, and what promises to be a good weekend ahead of us.
Get them fitted mate !!

Use the lead I have suggested for the RCA conversion, and set the gains on the amps to around 0.4 V - 0.5 V and all should be well.
As far as subs / estate goes, I had a similar problem in my RS4, as I didn`t want to lose valuable space. So what I have done is to fit the amplifiers etc hidden away, but to terminate the sub output on a socket that has been flushed into the rear 1/4 panel trim. That way I can use a seperate sub box and plug it in / out very very quickly whilst keeping all connections nice and tidy. The speaker box connectors and Banana plugs used by most sub boxes are perfect for this.
