it's blatantly obvious. Only parts you've modified are affected. Also, they really should prove your mods caused the problem to begin with. Finally, even then it's not VOID, it's a denial of that particular repair. If they refuse to fix your tranny because you abused it or put in some other clutch, your warranty is not void. When you bring it in later for blowing a cylander, they still have to prove some reason why they are not at fault for that too!
VOID implies the entire warranty, it also implies finality. Refusal of service is totally different and much more isolated.
2015 STi: Still Stock
04 STi, 04 WRX: SOLD