I'm trying to work out which of these to buy. As far as I can tell, the TDI 75 and TDI 90 can both be chipped for more bhp - 101bhp for the TDI 90? But given the TDI 90 has a different turbo set up, can the TDI 75 ever generate similar power/performance when chipped without compromising the engine? If it can, it seems the more sensible choice as there are more to choose from....but that may be the wrong conclusion. Even though the 1.6 FSI has 110 bhp, I realise the disadvantage is it uses more fuel and is perhaps slower through the gears. However if you are driving at speed (say 90 - 100 mph on the continent) is it significantly quieter than the diesel engine as this may be a good selling point?