pulling codes from an aftermarket alarm system is much harder than the oem key signal. there is a lot you can do to make it difficult to prevent theft, but also steps you can take to track after theft. i have a seperate battery connected to my gps module so if power is disconnected, the backup battery will power my gps for about a week. being that both are hidden away from the alarm system its not easy to find. the gps in the truck is very easily disconnected and then fordpass will not work. i also have my train horn connected as my siren output and my air tanks are aways full. 10 gallons of air goes a long way on a pulsed output. you want to talk about being loud and attention grabbing, a train horn is the way to go. when mine gets set off, it wakes up the entire street. also, aftermarket alarm systems have data modules. its very convienent and ties into the trucks system but the downfall is that it does tie into the system. disarming the oem system will disarm the aftermarket system and vice versa. so a hardwire install is best, but more time consumming. a data module is still needed if you want to have the long range remote start options that aftermarket systems provide, but they can be wired to not interface with the oem system. the aftermarket system will then disarm the oem system, but the oem system will not disarm the aftermarket system. this is the best way to go since disarming the aftermarket system is more difficult. most higher end systems will run you about $1500-$2000 installed depending on what features you want. my set up is as follows.
viper 5906v
dsm550 gps
506t glass break sensor
(2) 520t backup batteries from directed electronics
506m tilt sensor
pn8600 magnetic switch for tailgate and bedcover
dball3 data module but its only for remote start features so it keeps my system seperate from oem. this does not require you to have to disarm each system. i dont use the oem system at all, but you can, just requires you to unlock 2 different systems with 2 different remotes. but i will never use the data module to interface with the data in the vehicle. when the raptors first came out, i did several installs in southernca because the cartel was hopping the boarder and stealing these trucks quite often. i wired my system accordingly to make sure all points of entry were covered and i was able to track my truck regarless of where it went and what condition the truck was in (battery disconnected, siren/horn cut, oem gps/fordpass disconnected, etc)