Question: is sdi better than tdi?
Answer: Torque. I've driven both, and yes a 1.9SDI is slower than a 1.4TDI, but is much nicer to drive as it has so much more torque. SFAIK, the n/a SDI has 104ft/lb max, whereas the 1.4 turbo 1.4 has 140ft/lb max.