Well,
It was -7 celsius (very cold & extremely snowy), i had finished another day of school. Driving back home, i get on the highway and realized i couldnt go over 80km/h (55 mp/h?) cuz the whole car would vibrate pretty badly and it would worsen at higher speeds.
Im assuming its something to do with the drivetrain, cuz id put it on neutral and the vibration continued..

Note; lowered suspension with bilstein shocks, springs, straps and struts changed around two years ago. Wheels dimension are 225-45-17 on B6 rs6 rims

 

assuming you got snow as well. you may have snow somewhere on the drivetrain that is frozen on and causing it to be unbalanced. happens on my wheels all the time. To see if its snow put it in a heated garage until you think the snow is all melted then put it outside. Now you can tell if its the cold weather or if it was just snow.

 

nice, thx for the info.
I'll give it a try as-soon-as-possible, and i'll report back!

 

Sounds like classic snow in the rims to me.

 

it wouldn't do that if it was in neutral

 

The wheels still spin when you are moving with the car in neutral. Unless the vibration happens when you aren't moving?

 

Good News!
It was Ice on my rims! (both front-rims had some ice on the inner part of the rim and a bit around the calipers).

Took it off and drove it, no more vibrations! [except when over 115km/h (70mp/h?), but I've always had that issue even after several tires changes, alignments, balancements and complete drivetrain checkups]