Cobalt SS Network - GM warranty

Cobalt SS Network (https://www.cobaltss.net/forums/)

- 2.4L LE5 Performance Tech (https://www.cobaltss.net/forums/2-4l-le5-performance-tech-46/)

- - GM warranty (https://www.cobaltss.net/forums/2-4l-le5-performance-tech-46/gm-warranty-271188/)

So when i bought my car i purchased the GM warranty, but some time after that i found out that the car already came with a few mods (aftermarket headers, exhaust, motor mounts, pcm calibration, new fuel injection..) then i installed a K&N intake...so i was wondering...wouldnt this completely void the warranty? n when taking the car for a check up the told me that the car isnt running as it should, so they recomended me doing a tune... i need some expert's advice!
one more thing...my car is a 2.4 would all this mods make a major improvement on the car?
how fast could the car be really running?

the words gm and warranty should never be used in the same sentence without the word bull****

haha i feel u bro...soo many dumb ways to deny you from gettin service