first of all as a newbie here you may have noticed the chip vs ecu flash wars (bias towards one solution or another)
the bully dog module is not a resistor or cheap clone, it is actually a computer that can be flashed via the usb port on the back
my friend "sparke" has the digi cr installed on a 2009 with zero pump, cat or dpf problems, the module has not been detuned by the ecu and he just recently returned from a 1000km trip to the bc interior (williams lake) with better fuel economy
with regards to the ecu flashes being
"invisible" this is simply a lie, I have seen with my own eyes the owner of a v10 toureg tdi get his warranty discarded at Sports VW (maple ridge). His tranny failed, they hooked up the car to the
factory scan tools and found his "invisible" tune instantly, he was handed a $6800 bill for a new tranny, the service tech was "matt" who now works at euro wrench werks,
call him if you think this is not true
some dealers will do a warranty approved ecu flash, I believe it is REVO software
Some dealers of ecu flashes "tunio" will talk about vehicles on trailers because of tuning modules, after being challenged several times in these forums he has yet to produce one picture of a damaged car because of a tuning module; he has however,
bricked a member's ecu with a fubared ecu flash
if it was my car I would make this choice, install a tuning module that can be removed prior to VW servicing , this is a true "invisible" solution
if I went the ecu flash route I would go to Malone tuning, he is local, skilled and has a dpf friendly tune
good luck and consider all of you options
http://malonetuning.com/