Hey Greg, well there is no GTL race this Saturday. There is a GTR2 race instead, we are alternating between both leagues. So, if you have GTR2, you are more than welcome to join.
To answer your question, the one SJ GTL Carpack is the only carpack available and the only one you need.
About your comment, to be honest I have not driven Three Riveres recently yet. I did drive on it on my old pre-historic computer and I did not have the best of FPS from that computer, but I got by. I'lll post the race announcement soon and ask everyone if they have any problems. Thanks!