Hii,

   

   TSI is nothing but Turbocharged Stratified Injection or Turbo Fuel Stratified Injection. Its nothing but injection of fuel being optimized for better power delivery and better fuel efficiency and somewhat better emissions as well. You can understand this from the the fact that the earlier Polo which developed 105bhp, did so from a 1.6 liter enigne while the TSI polo does it from a 1.2 liter engine. A smaller engine also means lower tax as the 1.2l is lesser than the 1.3 liter mark.

Thanks!