This is taken from TonyJetta at the tdiclub forms, and adapted to what I did:
1) Remove battery box cover.
2) Disconnect ground wire from battery (10mm nuts)
3) Disconnect positive wire from battery - DO NOT ALLOW LEADS TO CONTACT EACH OTHER OR THE BATTERY TERMINALS
4) Looking at the battery box, on the outside, just to the left of the box, there is a hold down bolt; remove this bolt (13mm nut)
5) Remove battery; insulator blanket will usually come out w/ battery
6) Install battery blanket around battery
7) Install battery into battery box, in same orientation as original
8) Clean battery cable connectors and battery terminals using a battery brush (round)
9) Install battery hold down & bolt; tighten.
10) Connect positive terminal; tighten until terminal is not loose.
11) Connect negative terminal; tighten until terminal is not loose.
12) Replace battery box cover
From what I understand there is a 1% chance your car might not start after replacing the battery (the dealership mentioned it, but said they've never seen it happen), and the auto window function (where you press it once and it goes down or up all of the way) can stop functioning until a code is cleared (I think).
I replaced mine while keeping power with a second battery connected, this prevents any loss of power to the system while the change happens. You just need to be careful to make sure you do it correctly.
your best bet is 25'' ('' is inches)
6.2 quarts with a filter change
Change Your Life was created on 2006-01-25.
5-10-15-20-25-30
Idol Tonight - 2006 2006-04-25 was released on: USA: 25 April 2006
Not as easy as in other cars, first diconnect the battery, you then need to either remove or release the bracing bar that is positioned over the top of the battery, don't forget to release the battery clamp at the bottom, remove the battery, not a good idea in minus 25 C.
Martha - 2005 2006-01-25 was released on: USA: 25 January 2006
Martha - 2005 2006-04-25 was released on: USA: 25 April 2006
Today - 1952 2006-03-25 was released on: USA: 25 March 2006
Today - 1952 2006-05-25 was released on: USA: 25 May 2006
Today - 1952 2006-07-25 was released on: USA: 25 July 2006
Today - 1952 2006-09-25 was released on: USA: 25 September 2006