I am also in a very similar situation to you and am just about to buy the Audison Bit One – a/Tuning flexibility and b/private seller in the UK so getting it at a good price.
I noticed you have the 6 spkr system and you’re looking for TECHNIC’s HARNESS? I have a Technic Harness for sale that would work for your set up and much cheaper than buying from the US. PM for me details – I’ll do you a VERY good price (I’m selling it as I have the basic set up so no use for the harness – it still comes in the original box too!)
By the way, I just got back from Portugal this weekend – stayed at Vilamoura – it was beautiful!
Someone is selling the Bit 10 D in the UK – not sure if it’s sold yet but could save you some money I would think...
My set up will be..
Focal KRS 100s + tweeter trims
Audison Bit One
Earthquake Subs (under seats).
Infinity Reference 7541a 4 ch amp
Earthquake Sub spacers
PM me for the Harness – It’ll reach you quicker and be a lot cheaper – no Duty / import costs.