If got budget, K3VE-T or the new Myvi 1.5 transplant.
If not much budget lighten the car, take out whatever unecessary deadweight in the car, replace with carbon fibre, drop in airfilter (or open pod if manual) with heat shield, pulleys, lightweight wheels and engine management.
If really little budget drop in airfilter / open pod and pulleys and lightweight wheels.
If even less than that budget, save up your money for the above.