Funny you say that. I just got a call this morning from my Nissan dealership. Seems the reason that my Xterra won't start is because some of the wires in my aftermarket Viper alarm have burnt out. They asked where I got it installed. They said the workmanship was very poor. Now it is costing me several hundred dollars to have Nissan remove the after market alarm and "re-install" the OEM "alarm".