Question for 2.0 TDi owners

[ABCD]

Firstly welcome to you all. I was hoping you might be able to help me out with a quick question.

I bottomed out at the top of a steep driveway, seeming to scrape under the drivers seat. I got out to have a look and noticed a metal box like object pretty much directly beneath the drivers footwell a bit further back from the front wheel. It is about 25cm long (running parallel to the length of the car), about 10cm wide and at least that in thickness though can't see it entirely as it is surrounded by those heavy plastic shields underneath the car. The exposed surface is covered in a series of fins ? cooling fins. It is warm to the touch but not hot as in engine pipe/exhaust hot.
I had a look under a 2.0 FSi and this did not have it.
My question is a simple one - any idea what it is?
Cheers

[85Fuego]

I understand that this is the fuel cooler.

[Angryman]

firstly you need to ask yourself a few questions...

a. am i a member of any underground crime families or am I a gangster/pimp etc
b. Is the box ticking
c. Which enemies want to kill me