Probably gone over the top with this audio upgrade will have to keep is stealthy so the wife does not notice.
Hi Dazza, can you tell me a bit more about your audio please? 
Ive had the Hertz 163/165's on my wishlist for years now (along with a nice amp) 
Are you using the RNS510? I really wanna keep mine but they arent very amp friendly 
Any help is appreciated 
I am using an RNS-510 and a line out converter 2 channel in and 3 out. Extra one for the sub.
You can have a look at the progress here http://www.mk5golfgti.co.uk/forum/index.php/topic,90967.90.html
I could not get the ESK 163's to fit perfectly so i am switching to HSK's. And the mid fits perfectly.
Many people have told me not to bother doing the rears.
I did the rears in my Golf.......Dazza is right! just do the fronts and a sub....Plus spend as much money on the front speakers as possible. I used the ESK's and they simply weren't good enough (to bright and quite harsh sounding)
Also, when looking at amps choose quality over power. I chose a digital Alpine amp and I've suspected ever since that it contributed the bright sound.
I used my RNS-510 and sent the signal to an Audison Bit Ten. Fabulous piece of kit but absolute overkill for what I wanted to achieve so I would also recommend just a simple line converter. It would be cheaper and far easier to configure.
All that said, although I probably wouldn't go to the same extreme again, I would definitely consider adding a simple sub/amp to my CC.
