Sergeant Revels

This indeed was the solution! Thank you for your quick response in this matter - you may close this thread ^^

Thanks for that! However I still can't get it to work, i redownloaded everything *shrug*
And I have been using 'Speed Radar Lite' for the time being.

First, don't offer money here, that is against this sites policy from what I understand.  I have this and after installing I thought i was confusing too.  There is a youtube video that shows how to install and get it running but guy talking is not very good at explaining it, but you can see what he does.  I suggest watching it........a few times lol.  It is ready to use right after install but if you have addon's you will have to add those into the XML files.
 
Let me see if I can help out a little bit though.  Most of the changes in the XML files are in the main root game folder/ lspdfr/ data folder. 
 
In the customs folder go to the agency you want to add your vehicles in.  Let's say LSPD xml.  Open the XML and where it says vehicles, that is where you would add your addon vehicles.  You should see the other replacement vehicles (police, police2, police3).  Under the last vehicle press enter and add <Vehicle chance="whatever chance number, all must add to 100">your vehicle name</Vehicle>
 
Don't make any changes to the outfits in the customs folder.  I mean you could, but it is a pain.  I won't explain it here, just get your vehicles in.
 
Go Back to the data folder and select Agency.  Add your vehicles the same way.  In the XML you'll add all your addon vehicles to all Agencies.  Scroll down the file, you'll see. 
 
Then go to the Duty selection XML and open that.  Down toward the bottom under Vehicle Descriptions is where you will add new lines for your addon vehicles.  This XML is if you want your addons to show up in the Police Garage selection. 
 
If you want certain agencies (vehicles) to spawn at certain police stations then go to the Stations XML and find and change the police stations agency and script name.  Example the Paleto Bay is a sheriff station but I changed it to a SAHP station so my SAHP units spawn there.  Here is a sample of how the lines look. 
 
<Name>Paleto Bay Sheriff Station</Name>
<Agency>sahp</Agency>
<ScriptName>sahp</ScriptName>
 
That is all the changes you would need to make.  Try to study the way the lines are laid out in the XML files and you should be able to figure it out. 

You need the latest version of the following:

RagePlugin Hook
Scripthook V
ScripthookVDotNet

as JJ9856 mentioned,

BUT, in addition to that, you'll need to create a new folder called 'Scripts'. Inside that folder is where you need to place the two SpeedRadar files. 

Let me know if that helped... If not, I'll create a quick video for you. 

It’s relatively easy really, go into lspdfr in the gta v directory and go into data and find agency.xml, scroll down and find fib or LSSD(whichever agency you want to add to) keep note fbi agency doesn’t ambiently spawn, lspd will and LSSD use these if you want too see the vehicles driving around and as backup. 
 
Where is says <vehicle>model</vehicle> Just copy this line right underneath and set it as police old. Should look like this:
 
 
<vehicles>
            <vehicle>FBI</vehicle
            <vehicle>policeold1</vehicle>
            <vehicle>policeold2</vehicle>
</vehicle>
 
 
 
 
Also so if you have EUP go into custom inside the data folder and change the same line in the agency_eup xml.
 
if your adding to an agency backup.xml will not need to be changed.
 
this should ambiently spawn the vehicles around the map and allow them as backup, aslong as the agency ambiently spawns anyway. I.e lspd & lssd
 
 
edit: you can add <flag>SpawnsAmbiently</flag> 
 
To the flags if You want fib to spawn like police
 
 
 
Callam.