never found any RS rubbers that fit properly but what can you do .
Conversely I've seen a lot of poorly fitted Rares rubbers....................
I put a NOS stock one in mine recently and the profile of the Rares one I removed was very similar, however the Rares rubber compound was much harder than factory. This makes it hard to close the boot. The NOS one closes easily.
If the rubber leaks then lift it and run a bead of Sikaflex underneath, then reseat the rubber and close the boot lid. Should fix the problem. Or check the alignment of the channel - you can adjust it upwards with a mallet and piece of wood.