20" Bridgestone RUN FLATS - Vibration

First post here.

Here in US I was one of the first to receive a GLC 300 back in early December 2015.

Came with Bridgestone HP Dueler Sport Run Flats 20" (ON NOW) 32Psi
20-inch AMG MULTISPOKE (Black)

Car vibrates after 75mph... Slight vibration on the steering wheel...These tires have been changed over 10 times here at my dealer by warranty.

From Bridgestone first.. to Pirelli Scorpion RUN FLATS (made my car feel STRONG vibrations at any speeds) were changed then to...
Michelin Pilot Sport A/S 3+ (NOT RUN FLAT)which to me where best.
But then Dealer installed them misaligned; by 4,000.00 miles tires were eating away wrong due to misalignment.

So Manager got me back on the Bridgestone HP Dueler Sport Run Flats, because Michelin after 14 sets of trial and error(TWO WEEKS WITH A LOANER), were always vibrating...and he knew I will not receive car back.

I would think a GLC 300 2016 would glide through a smooth expressway here in South Florida...I want to have a floaty feeling.

Now I have the Bridgestone HP Dueler Sport Run Flats 20" and Im not 100% happy due to not having a smooooooth ride above 75mph.

Mercedes Benz - The Best or nothing...right?

Any thoughts??

Thank you!