I recently purchase a 2015 Toyota Corolla LE. However, it doesn't come with an alarm and the alarm option (Karr) offered by the dealer seem to be a complete rip over ($800 for the alarm). The remote entry button appears to be built into the key fob. Can I still get an aftermarket alarm? Would that render the car key unless? What types of alarm would you recommend? A lot of my neighbors have Viper / Clifford alarms.
The original key fob would conflict with other after market security, so you would need to park that remote in lieu of the new system. The starter kill is already in there (Universal Toyota transponder fuel rail cut off system) so you won't need that part of an alarm replaced.
Viper and Clifford (both DEI products) are fine, if not a bit complicated, but is suggest a system you can get technical support on when needed, and is designed for ease of installation.
(Crimestopper SP 101 for instance) has remarkable key less range, a very loud siren and a shock sensor. Does your door locks as well. But go with whatever you like, just keep in mind Toyota has already OEM installed security as it sits. Not complete, but the car won't get stolen.
I hope this helped some.