I am currently using a stock Proton Satria 1.3gli (year 2001) , my car is manual transmission.
I am planning to do an exhaust mod since my car is very underpowered, i have been researching but cant really choose a 4-2-1 or 4-1 extractor and a s-flow or straight flow muffler.

Can anyone give me some pointers, most people would ask me to go for 4-2-1 extractor and straight flow muffler but some are saying 4-2-1 with s-flow will be better for consumption.

My target for the exhaust mod is...