na in Vitz's case dunt try heavy plugs, heavy plugs need heavy wires, dunt even try to make life miserable, ghalti se agr wires short hogain due to heavy wires ull be in deep trouble.
Go to the spare parts shop @ khan motors or if u noe the phase 2 area, to SSAT colege k sath shop hai go there get a guard air Filter, Denso k-16r Plugs, Go to Amir @ PSO tell him mjhe lag raha hai gari ka pick up thora ghut gaya hai. change these plugs nd filter nd c if tuning is required. Dunt act childish over there werna lyk anybody else he wud try to Rip u off. nd tell him u need power.
he charges about 350.
plugs tme 520 tak ke milenge air filter wud be like 250 to 350.
if u need ur car to tell u shes fast. add a air intake (only filter) thats abut Rs.1000.
btw wat tyres are u using nd how much air presure??
if there "185/65/14". switch to 28PSI ul be happy. 30 nd 32 PSI wud make u feel the ride more handly but also make u feel it hard.
Cat convertor k bare mei VItz owners club mei bht kch likha hua hai. its a blockage in the Cylincer to clean Carbondioxide. but due to lead in Pakistani fuel it gets choked.
Secondly have u changed the ATF (automatic transmission fluid) of your car??
Vitz requires three 3 cans if u jst refill oil those are 450 per can. type IV i guess. uske bare mei bhe kafi info hai Vitz owners Club per. nd il recomend u to go thru it ud be enlightened alot about ur Vitz.