Grimwatch

Ok so a few days ago I stumbled across a youtube vid of The LCPD mod this site is home to. I promptly re-bought GTA 4 over steam, spent a full day downloading it (I live in Panama so yay for third world DSL lol). I got the mod installed properly but now Im totally lost. How do I add the custom police cars (models, skins etc) into my game files? I have looked at their read me's and its all nice and vague. After much poking around I found a program called Spark IV. I followed its instructions and it comes up with an error that says my game version is too new to be supported. So this leaves me having to do this manually. I have no idea how. 2 days in now and Im beginning to get immensely frustrated by the overwhelming complexity of this. Ok Tom's suggestion worked, kind of. I got some of the skins in but most didnt show up. Not sure why. Im guessing the next step is to get this ELS 6 installed since all the cars I did get have no light effects now, just siren.