I just had one installed in my 2.5L, it's awesome.
I bought an Active Autowerkes kit ( http://www.activeautowerke.com/viewproduct.aspx?id=Product19 ) and had Turner Motor Sports ( http://www.turnermotorsport.com/html/index.asp ) do the install, talk to Marko. Performance is great, smooth build up of power, start to feel it around 2500 RPM and it just keeps pulling. So far I have auto crossed with it 3 times and gone on an 800 mile road trip and no problems. Milage went from 25-26 to 22-23, but I tend to enjoy driving....I just wish I had done it sooner. Kit cost $6500 and install was $1200. I'm planning on getting it dyno'd in he next couple of weeks and will post the numbers.JCZ3
2004 X3 2.5 Silver Gray
2004 325xi Titanium Silver
2000 2.3A Dakar Yellow
AA Supercharger,Dinan exhaust, Dinan stage 2 suspension, KMAC front camber plates, LeatherZ Mark1, 3M Roadguard and Alpine CDA-9857 HU