The best suggestion i can give is to swap engine 1.0 to 1.3 once you are tired with 1.0 and its noise...
these cars were designed for Japan...which have awesome fuel and atmosphere...but in pakistan with bad fuel 1.0 gives noise...and often cat converter gets choked...
but this is hottest of all, 1.0 in vitz....
if you swap to 1.3, you can get pleasure of 1300 without any taxes.....
import tax on 1300 cc is too much