If I were to replace my bumpers to after market kind, what other parts of the warranty would I void, beside the bumper, due to replacing the original.

 

Don't let these guys get you so scared. The bumper will void the bumper, and as far as I know the bumper isn't under any real warranty. Unless under some seriously absurd circumstance the plastic bumper falls apart completely and disinigrates before 3 years or 36k miles. Beyond that, it is just warrantied to be a bumper. You will be fine.

The warranty voiding is often justifiable, when you slap on 37" tires, a 5" lift and something in the drive train wears out - it is absolutely reasonable to assume that your modifications played a role. These are the complaints here.

The MMA protects you from malicious or arbitrary revocation of warranty.

Just do it.