Well now the Z4 is sold I have some bits that never got used for sale.
Firstly a pair of brake calipers that can be used as part of the how to below. They are the same as the later 3.0l si calipers and provide better braking. You will need the bigger discs and pads, but all is explained in the 'how to'.
http://www.z4-forum.com/forum/viewtopic.php?f=24&t=8399&hilit=brake+upgrade
My personal opinion is the pre-face lift cars had poor brakes and I imagine BMW agreed, hence upgrading them for the later cars. I then went on the hunt for a pair of front brake calipers. I eventually managed to find a pair from a E46 330, the pistons have some surface rust but the seals and carriers are in good condition. I spent a bit of time with a wire brush and cleaned the surface to allow for paint. Using a decent caliper paint kit, the calipers have been painted black. If you are very picky you could repaint them as they have some marks from where they have been stored in the garage. Please have a good look at the photos to see what I mean, but the important surface that can be seen is perfect on both!
Check the 'how to' carefully to see what else you need. From memory you will need 17" inch wheels or bigger to go over the caliper. I have never fitted the calipers but did line up the carrier and caliper to see the size difference. It is hard to spot until you have both small and larger calipers side by side. Sorry to say I can't put a guarantee on the calipers but I think they are good to go!
I will accept £80 for the per. Collection if possible, near Gatwick, as these are pretty heavy!!!
Firstly a pair of brake calipers that can be used as part of the how to below. They are the same as the later 3.0l si calipers and provide better braking. You will need the bigger discs and pads, but all is explained in the 'how to'.
http://www.z4-forum.com/forum/viewtopic.php?f=24&t=8399&hilit=brake+upgrade
My personal opinion is the pre-face lift cars had poor brakes and I imagine BMW agreed, hence upgrading them for the later cars. I then went on the hunt for a pair of front brake calipers. I eventually managed to find a pair from a E46 330, the pistons have some surface rust but the seals and carriers are in good condition. I spent a bit of time with a wire brush and cleaned the surface to allow for paint. Using a decent caliper paint kit, the calipers have been painted black. If you are very picky you could repaint them as they have some marks from where they have been stored in the garage. Please have a good look at the photos to see what I mean, but the important surface that can be seen is perfect on both!
Check the 'how to' carefully to see what else you need. From memory you will need 17" inch wheels or bigger to go over the caliper. I have never fitted the calipers but did line up the carrier and caliper to see the size difference. It is hard to spot until you have both small and larger calipers side by side. Sorry to say I can't put a guarantee on the calipers but I think they are good to go!
I will accept £80 for the per. Collection if possible, near Gatwick, as these are pretty heavy!!!
I will pop them on eBay at a starting price of £20 unless somebody wants to make me a better offer now. As I am in the process of buying a new house I need every penny I can get! 
