So far recently all the gaskets were replaced and the car feels more alive but i want to try make this car have a little more power and was wondering if there is anything i can even do to the engine that would improve its power without needing to add a turbo or messing with the internal components. Maybe better injectors or something might help but I'm not too sure. (i have the Daihatsu Sirion Deluxe [facelift model])

The only current modification that i have done is have a new stainless steel exhaust done from just before where the standard muffler was. I only did this section as it was cheaper and the muffler had simply just rusted away so there was no saving it. I believe from that section onwards the pipe was increased to a 2 inch pipe from i think a one inch pipe? Not fully sure on that measurement but it is larger. When i had that exhaust done i did keep a muffler in but asked for more of a free flowing muffler so i believe there may be a small improvement there? Either way it has slightly improved the sound of the car especially on deceleration. I don't know if this is actually hurting the power output since its so far on the exhaust.

I was also curious if a "cold air intake" would even help the car since nothing else is really changing fuel wise but maybe more airflow might help a little with that exhaust or would it just be such a minimal thing to install that its useless. If anyone has a audio/ video clip of an aftermarket air filter, and what difference in sound it creates.

I'm also open to any panel/ other upgrades that can be done to the car to make it more personalised.