OCAC is right. If the problem caused by the remote starter, the dealer will void the warranty on that. For example, when people cut the wire somewhere when installing the remote starter and have to replace the whole harness, or the remote starter control unit failed n caused no start ( That's what usually happened that I seen in dealer ). In this case, dealer will void you warranty on repair those issue. Like if your transmission having trouble, n they will not void your warranty because you are having a aftermarket remote starter.
not necessary. Warranty will NOT be void if the alarm is from dealer. It doesn't matter where you install from. Usually private garage can purchase OEM parts from dealer and install them at a lower cost.