Exhaust system

Still learning and I'm always curious about my father's car - Subaru WRX 2018.

Last year, my father won an exhaust system on their car group raffle WRX (forgot the name). I made a research and this is the actual item https://www.subaruonlineparts.com/sku/d441sva100.html.

Now my questions are:

Is exhaust system plays a big role on tuning a car?
Where can I get a proper help to install this?

No tune needed for catbacks. Just throw it on and go

You should be fine. The STI exhaust (linked) was a factory upgrade option for my 2015 WRX. So it?s made to run with the stock tune.

Also, HPTuners cannot tune 2015-2021 year model WRX cars - only the WRX STI models. :(

You will need a tune if you ever change the catted pipe towards the front of the engine or do any major intake/emissions changes. For the catback though, as mentioned, bolt on and enjoy :).