does anyone know where I can buy a dinan intake online?

dinan's homepage?
http://www.dinancars.com/store/High-Flow-Intake-03-05-c-480-p-1332.html

any other sites? i rmember seeing it somewhere for $300

eBay has one every now and then, but you might want to try and negotiate a better price with your local Dinan dealer (if you have one close by, which isn't always the case, unfortunately). Also, you might consider a WTB (Want To Buy) posting on the various Z4 sites.

Personally I would run the RPI intake for less than half the price.

K&N also make the Dinan high flow air filter and they're available as well for less money.

Personally I would run the RPI intake for less than half the price.

K&N also make the Dinan high flow air filter and they're available as well for less money.

+1 I couldn't be more happier with RPI + skid plates. It's much easier to installed than Dinan. I think you have to remove the front bumper to install the CAI.

I haven't driven enough to get the full benefits yet. The car intake is a bit louder with better exhaust notes.

RPI (supposedly) doesn't fit the 03-05's.

That was my understanding when I got my Dinan.