I have a factory security system coming. (E-bay $111)
I understand I just replace the TSM with the TSSM under the battery.

Update:
Instal went pretty easy except for disconnecting the neg terminal & removing battery. Wow! is that a tight area.

I read some other posts suggesting the need to have the system/FOB set-up by the stealer (including a local stealer service writer). Set-up directions were very clear, - no problem at all.

Now to get a siren added