good question.....we has been experience before.it will be depend to the installer how there do it. but the correct way is arm the alarm then the engine still running after just switch off by the timer.
Have a set Apexi muffler for sell ,using 1 year.plug and play.
The muffler still install at my car,will open up end of this mon.
The Apexi muffler P/N: 149-T006. New unit more then...