Its simply better to get your sales man in your trust ask him, If installing a key less entry would ruin your warranty and also ask him if you get it installed from them what are the circumstances.
Other then that cutting of wires would void the warranty, But if installing a keyless entry makes a sound in the suspension the warranty for suspension is valid,
The only thing that would be void is that in case of a short circuit, battery drain due to any faulty wiring wouldnt be covered.