[IgorM]

How important/functional is this piece?

What does it do? It's paper thin and searching online all I found was this:

AFM 34 is Victor Reinz®' most successful gasket material of all time. This aramide fiber-based classic is completely harmless from a physiological point of view and has all the important approvals (TA Luft and FDA-compliant, to name a few). Universally useable, this gasket material is the perfect sealing solution for a huge number of media and a wide range of temperatures and operating pressures.

I replaced the front spring today and forgot to put this back, should I really need to take it all apart to put it back on? What does it actually do?

It came from where the top hat connects to the car....

Thoughts?

[S4NoMore]

You're probably fine without it, unless you notice anything strange (squeaks).

I believe it's intended to prevent any noise from being generated where the strut mount meets the body.