My understanding is that on the B6 there were different versions of the 1.9 (1896cc) engine depending on the spec of the car you wanted. The 1.9 was the standard 4-pot diesel unit on that car (as it was on the B5). It got messy with all the different versions of that engine, especially when the PD units came in later on... The 130 was pretty much the best one of those.
When the B7 chassis came out the standard diesel unit was the newer 2.0 (1968cc) engine with 140bhp, and then later with 170bhp. The 1.9 unit fitted to the B7 was more of a budget offering with lower power output, better economy and lower CO2. Its quite different from the B6 1.9 engine as far as I know.
They still remap pretty well and you can get them in S-Line spec in the B7 and so you can get a lot of car for not a lot of money. Power output aside, whether the 1.9 engine is better than the 2.0 unit is open to debate.
J
