Various Model Remote Starters, Remote Info Sought

I'm not purposely not putting vehicle models in as I've been coming across alot lately with a few of my customers as I'm a Locksmith, welcome to my world! I do keys, programming, diagnostics, etc for individual but also have a few commercial accounts. These commercial accounts are getting more and more cars that are coming from auctions with remote starts, possibly alarms unbeknownst to the customers. They'll ask me to create a key with the remote and when I look under the dash as I always do I will see an aftermarket system installed and ask them where the remote is and they'll say it doesn't have remote start and then when I show them a picture of the box, wiring strapped up in there they generally look at me dumbfounded. I also look for the GPS systems because I'm very aware of what those do as well because I have a few buy here pay here lots also. I haven't dug to much into it as I haven't said anything to the car dealers as I know they'd want me to find the remotes. I Want to make sure I can do what needs to be done if asked which is why I'm looking . I will say I have some tooling where I can create various vehicle remotes from scratch from universal remotes that I can program via the icc, frequency as doing keys I make universal remotes for alot of cars that I deal with I'm looking how to put these boxes into programming mode, take them thru the process. I also know on some remotes I can use a existing remote to do a multi lock press and hold with the vehicle starting after so long. Is there a cheat sheet that shows what brands do what that someone may have created with the programming info so I have something to reference. I'm sure the remote start industry is ever evolving as time to time I get requests to install and when I look up information it doesn't seem to bad on a initial stall level. Also more and more I'm getting customers say "how do I get a remote for this", I look under dash and low and behold find out they bought a used car with a aftermarket system already installed Then I get the case of mid 2000's Chevy Tahoes that have aftermarket remote starts that when installed and it's widely known in locksmith community that they keep the vehicle from being able to be programmed with a regular remote so we generally tell the customer we need to remove the remote start to program a remote in In about 90% of these cases they, the remotes program in and problem solved. .. IF I can get these remote starts some remotes I can charge $100-$200 depending on the situation. In some situations I have to clone the chip to be able to program a new key in if for say like on a Honda the ignition assembly locks up due to a worn out cylinder. The last one I did I couldn't communicate with the ECM whatsoever. Luckily it wasn't the newer newer high security immobilizer chip and I was able to clone a new one in using the old one. Any and all help is appreciated. Also if needed I can pm you my email address if you don't want to post any shortcuts, etc here on the forums for secure reasons, etc. Just seems more and more I run into these issues and if I can solve these issues I can also charge a premium because the customer which is generally a few car lots once a remote and at times they'll say they don't care what it cost just get a remote for it.Any help is better than no help.

only thing I can suggest is smart control if you are in Canada, or Carlink/Linkr if are in the States. These are the only products that have multi brand support. (Directed/Compustar/Ads/Voxx)