I've created a graph to show how the 200PS TFSI and 170 TDI distribute their different power and torque curves to actual road speeds and gear selections. You'll see that the TDI has more power in gears 1-3 upto 4000 rpm and about equal in 5-6 (dropping off a little a higher speeds). TFSI gains advantage staying in gear longer and using the extra 30hp 4200-6200rpm. For in-gear acceleration they should be about equal upto around 4000rpm. TFSI only need 2nd gear to reach 60mph, TDI requires 3rd gear. From this data the best shift points for maximum acceleration to top speed are; TFSI (6200rpm) 2nd 36mph 3rd 58mph 4th 82mph 5th 110mph 6th 140mph TDI (4200rpm) 2nd 23mph 3rd 41mph 4th 64mph 5th 93mph 6th 119mph No question the TFSI is faster. The additional torque does give the TDI some good/comparable in gear figures but sustained acceleration will suffer due to more gear changes. For everyday driving the two cars are quite similar and the fuel ecomony advantage (10-15mpg) of the TDI could be a good compromise to loss of top end. Which is my choice. Thanks to Dave (h5djr) for Gearbox ratios.