Quick update for anyone interested enough, or bored/mad enough to be following this thread...
Back from a weekends' biking (360km total!) in the hilly south of Holland and intended to crack on with the CCV system replacement today as well as re-seating the crankcase gasket. However, on opening the Febi Bilstein CCV kit I realised I've only gone and ordered the non-cold weather kit! What a tosser.

I know I could certainly use the delivered kit and to all intents and purposes it's easier to fit due to the lack of insulating material but I want to do things properly and also reduce the risks of the hoses and valve failing in the future, so will re-order the cold climate kit.
Taking advantage of this unexpected delay, and on reading various forum threads I've also decided to replace the 'Distribution Piece' item 5 on realOEM: http://www.realoem.com/bmw/enUS/showparts?id=BT52-EUR-09-2003-E85-BMW-Z4_30i&diagId=11_2879
which sits on top of the inlet manifold. This has 6 connecting O rings which can harden and fail and compromise the vacuum system as well as the manifold itself gunking up so maybe it's not absolutely necessary but why not go the whole hog eh?
For anyone thinking about attempting this procedure and like me is not a trained mechanic, it's well worth doing a bit of research online. There are a LOT of forum threads hither and thither as well as a veritable plethora of youtube videos, all with varying quality and aptitude displayed by the posters, but so far the best guides I have come accross and will be following are as follows:
CCV Replacement FYI - M54
http://www.bimmerforums.com/forum/showthread.php?1376457-CCV-Replacement-FYI-M54
BMW 330i 325i E46 CCV Replace
[youtube]ZDP8Dma0nUs[/youtube]
(I won't be removing the intake/fuel rail however)
And there are numerous other guides and instructions around the interwebs I'll be referencing too.
Progress to follow...
By the way, I know there's a few keen road cyclists on here and I just wanted to recommend sticking triathlon bars on your bike. Bloody hell- I got up to 85km/h coming down one hill at the weekend! My eyes were out on stalks before I chickened out and pulled on the brakes. Bonkers.
On the flat, in triathlon riding position, hunched over the bars and pushing back and down instead of just down on the crank I'm gaining an average of 10-15km/h overall due to the better aero.
I just need to reduce my fat belly a bit more to accomodate the riding position better :lol:
