Before you ask, no, the quests in mind don't give stat buffs to torsos.
So, if there's no stat boost for the torso upon quest completion, what would the quest reward be? It's both simple and complicated, really. Upon quest completion, the pilot would receive a unique paintjob perk that matches the theme of the torso that they've mastered and would change the overall paintjob of a build to match the unique paintjob of the torso.
As for the mastery quest, they would vary from torso to torso and would be based off of the torso's strengths. They would only be available once a torso has been divined, however, since divine is the highest a torso can go and mastery would signify a pilot's true bond with a torso as they would have to work their way to divinity then work for quest completion.
I bet you're likely wondering as to why I thought of an idea like this.. And well, to put it shortly, I thought that unique paintjobs would provide a much wider range of cosmetic variety outside of a simple handful of perks and paints that hasn't seen many additions as of late.
Also, yes, I've thought up of examples for torso mastery quests. If you'd like to see the list of them, here you go:
Torso Master Quest Examples
Broken Determination (Energy-Free Armor)
Defeat 500 enemies while energy-broken Achilles' Heel (Avenger)
Win a total of 50 arena battles. Only battles where the pilot endures a shutdown or an energy break will count towards quest completion Relentless (Any Spectral Armor-Class Torso)
Absorb a total of 10,000 damage from any source of damage while having no resistances Weight Reduction (Any Interceptor-Class Torso)
Defeat 350 enemies using lightweight equipment Return to Sender (Zarkares)
Receive a total of 2,500 heat damage and deal a total of 5,000 heat damage Critical Conditioning (Archimonde)
Defeat 250 enemies while HP, energy, or heat is at critical level Stormbreaker (Naga)
Energy break 250 enemies while on the verge of being energy broken Incineration Order (Windigo)
Shut 250 enemies down while on the verge of being shut down Ungodly Wrath (Brutality)
Deal a total of 6,000 explosive damage or 6,000 heat damage
I would come up with more but that's really all I got for now and I don't want to make the list too long or else people will likely get bored of reading it and just skip past it.
However- I could make a separate topic where there would be an entire list of torso mastery quest ideas for each torso but I won't do it since I'm not sure if anyone would be interested in that.
But anywho- That's all I've got for this topic. Thanks for reading and I wish you all a nice day/night.