aftermarket and warranties

i got a 1500 4.8L and i'm looking to throw on flowmasters cat back system with a K and N FIPK. i bought this truck used with the 36,000/3 year bumper to bumper warranty. do these aftermarket products void my warranty?

also, i travel on the highway alot so i'm looking for an exhaust that is quiet on the highway but rips when i accelerate. american thunder or force II?
thanks

I dont think the exhaust will, but the FIPK might, but I doubt it.

Go with the 70 Series Big Block II Flowmasters. They will be perfect for what you just described.

Mike, I have an '01 Silverado X-Cab 4x4 Stepside W/ the 5.3L, And I have the cat back system & K&N FIPK And my dealer here has had no problems what so ever with the changes. The only thing they have refused to pay for is my Axle seal leak, And as I have installed a lift kit & larger tires, which put more of a strain on the axles. I guess it really depends on your dealer. I hope this helps. You'll really enjoy these mods on your truck!