Ammar, i agree with most of the guys,
but what you have to rememebr is ,
unlike out side world in pakistan if you will do any kind of engine mods you will lose money , unless other wise you are trying to put in a turbo deisel in your swift:)
as long you are not selling the car and keeping for fun and show off its kool.
Depending on the $$$ you want to spend i will strongly recomend if you are on low budget
go for straight through mufler and pod filter.
medium bugjet
cold air intake may be, but it wont make much difference for an N/A car.
go for the clutus GTI engine and trust me it got guts
hi budjet
go for tubo .
if i will be you , i will save money and will go for JAP Cultus GTI engine