Did you replace the fluid in the fan clutch? There is a thread on mud about the Mod. I did not change the temp setting screws, but replaced the fluid with 8,000 CST I bought at a Remote Control model shop. Noticed a big difference. I would use 10,000 CST next time.
Do you have dual batteries, lights or something else in front of the grill to restrict airflow?
You can add an aux fan, I did because I have a packed engine bay with dual batts and an SC
Edit - I see you took off your PIAAs. I use to have to take mine off when towing over the mtn passes before I got my aux fan
Ken Romer - K0ROM
02 Kimberley Kamper
09 BMW Z4 sDrive30i