Probably. Or some string? :-)
It'll depend where the noise is coming from. If it's coming from the back of the car it may be a leaky exhaust rather than the exhaust system absolute.
Hmmm. To a degree, except, depending on the variant, the VAG's key strength is its willingness to pull hard from ~1,500 rpm.
Yes but...
That's only a relative perception; perhaps it's true to some small degree, but this is almost certainly because the difference between the TDI 90 pulling hard at 1,500 rpm and 3,000 rpm is much smaller than the TDI 130 at the same engine speeds. if you see what I mean.
Yes, but there's pulling happily and wheelspinning. :)
One of the key strengths of the 1.9 TDI 130 is that it's arguably the best blend of the 1.9 range (some argue that the original TDI PD 115 is a better compromise because it's quieter). The 150 has a reputation for being noisier and thirstier, but I suspect a chunk of this is associated with the owners using the power. The TDI 90 is a good economy choice, the 110 is a better one (it tends to be just as economical but is quicker). The latest ~100 PS is probably a decent compromise between the two...
The key VAG 1.9 TDI weaknesses are the unwillingness to rev as hard as more modern, multivalve peers. And their homes, but that's another argument... ;-)