1999 Infiniti G20 Base loud noise buzzing /rattling/ vibrations

OK this is a real head scratcher.I have 58,000 original miles on car. The car runs beautiful but as soon as I get up to 55-60 mph this buzzing /rattling/ vibrating sound starts out, the steering wheel does NOT shake. It sounds like its coming from the engine compartment but close to the bottom of windshield.I had noise before but I just replaced front struts cause they were bad. And the pass side axle was bad too. The mechanic were even baffled by the sound. Well I dont know how good of mechanics they are it was at Mavis Tire so I wouldn't expect them to know everything about every car. This noise gets louder the faster you go between 60 - 80 I tested on highway going up to 80 then letting my foot of of gas pedal to see if it was something to do with the fuel but it didnt stop as soon as car slows to 60 sound stops. It is really driving me nuts.I just drove 10 hours from Long Island to West Virginia and had to listen to it. Lol so u can imagine how I felt.I checked as much as I could think of like license plate rattling to looking for loose parts under hood to un-balanced tires but to no luck. PLEASE HELP ME !