Tuning engine

Hi there!
Ive figured ill ask a question here…
Its about tuning an engine.
In my case it is a 1.3 sirion2 2005 engine
And since its non turbo i qas wondering about the options there are to increase the power a little bit without swapping the entire engine now ive found something like this: https://www.gantuning.com/chiptuning/daihatsu/sirion/1-3i-87hp-120nm-120nm-n/
Anyone here has experience with these sort of things?
Im not saying i am buying this but i know local tune shops offer similar options and i just would like that little bit of extra punch when i decide to pass other traffic on the highway
If anyone has experience or advise please let me know