I experienced similar noise.. .initially sounded like separated belt. Inspected tires for telltale signs but no. It appeared to be intermittant so I have waited for it to develop further.
Now 5000 km's later it is sounding like 35" mudders at highway speed. suspect support bearing as sound is more pronounced while turning right. can actually get it to make noise doing a "slalom" at 40 km/h. on right hand turn only.
Heading to shop tomorrow to do regular maintenance and have this investigated. will feed back results.
98 mystique, auto, duratec V6, 112,000 km's
