[NH335i]

Soo i just posted this the other day but it was on someone else's post.
Anyway.

I just called my local bmw dealer.
service said that just rattle doesnt constitute turbo replacement.
Wtf. It only happens once every two or three times i start my car.
But when it does. It sounds sooo shitty.
Does anyone know what makes it come and go?
I was all happy thinkin i was gonna get new turbos and this service individual kinda just discouraged me alot
They said it has to be losing boost as well.

If so, should I go to another place to get my boost levels checked rather than the stealership? So atleast Ill have an idea going into them trying to get new ones.

Any help would be phenomenal.