Have a Dinan Tronics Sport tuner, this is perfect for n20 and n55 e89's. I used in my 428xi with great success, noticeable for sure. I just got an 09' z4 35i so that is n54 and it isn't compatible. Looking for $175 shipped or OBO with shipping included for reasonable offers (not $100). Will ship via FedEx, USPS priority with tracking or UPS, shipping from Brighton Michigan.
Thank you