vibration w/ high speed braking, will dealership know about pads?

[AlpineMsix]

So i replaced my brake pads to the axxis dustless pads and everything was fine for about 6-7months and now im getting a pretty big vibration that is associated w/high speed. when i brake at around 30-60mph everything is fine..,


but if i drive aggresively; lets say if i go around 80mph and apply the brakes kinda of hard and then speed up again and apply them agian, i get a real noticable vibration in my steerring wheel.

My question is; will the dealer know from looking at my pads that i have non oem pads.(they have been on for 6months now)

and shoudl i also remove my rear spacers just so they dont try to blame it on the spacers?