1-way remote start systems are adequate when the user is close to the vehicle and can witness the vehicle start. Consider a two-way system for added range and command confirmations.
2-way remote starters communicate back to the user confirming a command has been executed. (doors locked, the vehicle started, etc.) Therefore you do not need to be physically near the vehicle to confirm a command has been executed. Greater range than 1-way systems (Up to 1 mile).