I am sorry to hear of the repeated problems with your Spyder. I have been in a similar situation and it is incredibly frustrating. It takes a great deal of patience and working back and forth to resolve these things, especially if your dealer is less than excellent. It takes time, too. I would suggest that you jump through BRP's hoops at this point. Have your guy at BRP contact the dealer and set up the "one more time" repair they requested. They will likely advise the technician or put him in contact with BRP dealer tech support to try to work out a solution. If that fails, then go ahead and let them fly out their ace factory technician. It pays to let them run their course with their preferred solutions.
If that fails, then you still have recourse to contact a lemon law lawyer, serve notice under the California lemon law, and proceed with legal action. Only about half the states have lemon laws that cover motorcycles, so you are fortunate to have that as a backup. Be aware, however, that such an action takes a long time to accomplish, will meet with strong resistance from start to finish, and will cut you off from any normal relationship with your dealer or BRP, and likely from further repair attempts until the case is resolved. That dealer may refuse to service your replacement vehicle, too...it has happened. As such, legal action should be a very last recourse. It can be worse than the original problem sometimes. You should remember that the clock is ticking in regard to legal action. Find out what the conditions are and be sure you meet them if you decide to go this route.
I wish you well in getting your problem resolved. I think your Spyder can be cured, even if it takes a new wiring harness and VCM (Vehicle Control Module). The BRP factory techs have tools that the dealer techs don't have, and can likely pinpoint the difficulty. Grit your teeth and give them a chance.