Maybe if we are being totally honest, outside of like maybe the outliers when it comes to exhaust upgrades from stock (new v4R comes to mind) - I don’t think mortals such as us with names not rhyming with Sossi and Barkuez aren’t gonna be able to tell a few HP gained or NM torque in a specific rpm band.

I’ve always seen exhaust upgrades for what they are - just an exercise in vanity (so it looks good in our eyes) and wanting to have a sound that excites us while we ride (often louder than stock but sometimes also for enhancing the engine’s characteristic note).

I’ve never done a exhaust swap and tune expecting to go considerably faster because of it or improve performance in any meaningful manner - without severely compromising engine longevity or safety that is.

Definitely get one of those compression sleeves from shoppee so you can put on the jacket and take it off without feeling like you’re fighting off a monster to do so. As for a shirt, like some of the above said a simple cotton or dry fit T-shirt would do just fine.

The undergarments sold by the brands are typically for the race suits.