A nice summary of what is needed to get RC8 to its full potential is
here.
It was already mentioned but it is worth stressing again, they are a pain to collimate and you will need a Tak collimation tool which is not cheap.
Long focal length will make it difficult to get good guiding results, especially if you are just starting. You may end up needing an OAG.
RC8 and HEQ5... did you check the weight limits? The stainless steel RC8 is 8kg already.