Shakes or Wobbles problem
2004 BMW 540i V8 Two Wheel Drive Manual 59000 miles

I have a 2004 BMW 545 with a manual transmission. I have been experiencing a vibration when cruising at around 65 MPH. Anything above or below, it goes away. I had 4 new rims and tires installed and roadforce balanced. The rims/tires checked out fine. I thought maybe the parking brake drum was warped because someone previously installed the returne springs wrong and the parking brake didn't release correctly. The vibration was still there after I removed the parking brake shoes though. The vibration comes through the seats and is speed dependant only. If I downshift to a lower gear like 4th or 5th, it is still noticeable. I was wondering if maybe the rear rotors could be warped enough that they are casuing the vibration however, I get no vibration when I apply the brakes.