Bit sad but just been having a look at power curves for the two 2.0 TDIs and the 2.0 TFSI engines (from the superchips website) - i opened the pdfs and overlaid them on each other.
Noticed some interesting things:
1. The 170 TDI has awfully low torque at very low engine speeds, ie, tickover and just over - in fact up to 1200rpm the 2.0 petrol has higher torque - guess this would mean the 170 would be easier to stall than the 140 or even the petrol! (if it were manual)
2.The 170 TDI over the rev range 1200-4500 is far more powerful to the 2.0 Petrol in every way, torque and power - only reason petrol is faster is because at that point you dont need to make a gear change and the petrol goes a bit further up to 6000. If you had a rev limit of 5000 on the petrol it would not be able to out-accelerate a 170 TDI. (yeh yeh stupid thing to say because it doesnt! lol)
3. The raw power figures between the 170 TDI and 200 ps petrol are not as far apart as the figures suggest (30) as the superchips curve shows the petrol makes exactly the manufacturers quoted power 196bhp and the TDI makes more 179bhp - which means actual difference between the two is only 17bhp - strange why this would be the case that audi under quote power on diesel but not on petrol?
I know not a very scientific way as the figures may not be accurate and may not be the same for all cars - but as a quick overview... hmmmmm