Thanks very much for your excellent instructions for replacing the Touareg battery. Here are some additional things that I learned.
CHECK FOR FOREIGN MATTER IN TRIPLE SQUARE SOCKETS:
There was a small pebble in the socket of one of my 10mm triple square bolts. I overlooked this and nearly stripped the bolt head before discovering and removing the pebble so as to enable full engagement of the bit. This could have been disastrous because this bolt was torqued to more than 150 ft-lbs. None of the other bolts was nearly so tight. When I reinstalled the seat I torqued these bolts to 50 ft-lbs. This may or may not be close to VW's designed tension, but at least I know they won't be that difficult to remove if there is a next time.
I used the Interstate Mega-Tron Plus MTP-93 from NAPA for less than $120. Any group 49 battery should drop in the space, but it should have a common vent that can be directed outside the battery box.
USE EXTRA CARE WHEN TILTING THE SEAT REARWARD:
I was careless when I tilted the seat back to get at the hardware below, tearing loose the wiring harness where it was secured under the seat. During reassembly I repositioned the harness in its carrier and secured it with some sturdy tie-wraps.
FORWARD BATTERY HOLD-DOWN:
This battery was not compatible with the forward hold-down in my 2004 Touareg V8. Newer models may not have this issue. Rather than modify this hold-down, I judged that the battery would be secure if moved forward all the way to engage under the flange hold-down built into the battery box and then clamped with the rear hold-down.
The vent of this battery was different from the original equipment battery. I found a piece of plastic tubing that seemed to fit securely, then cobbled a connection with the original vent line.
Thanks again for your timely posting of these instructions.