Great thread Sniffer,thanks.
Just completed mine,slightlly different amp mount location as I dont have the raised boot cover as no CD changer,amp mounted on plastic tray below boot liner.
I used two 5m long phono cables to the head unit signal wires and just snipped the ends off.
It sounds great already,I'm awaiting my sw-8's but as you say,theres already a big kick from the factory subs if a little distorted at full volume.
Big thanks to Anneke at Sytner for suppling the tweeters,really great service from them and a MASSIVE thanks to Gizze,he's a top bloke and an internet legend!