We have 2 DroidX phones. They both paired fine to the 2 vehicles listed above. The BT connection is dropped instantly on incoming calls while the actual call stays active. This necessitates using "hands" for a handsfree system to either put the phone to your ear (illegal here in WA state while driving) or the added distraction of trying to find the speakerphone button while driving. The Acura is listed as compatible:
http://support.vzw.com/pdf/bluetooth_car_kit/droid_x.pdf
The Infiniti is not listed specifically. I will say that we have had no previous bluetooth issues using our previous phones: Blackberry Bold 9650, Blackberry Tour 9630 and Motorola z6TVs. All 3 functioned flawlessly with the same 2 vehicles.
Please advise next step. Thank you.