Transferring this faIl, taking a non required course, thinking about dropping it for a W. Bad idea?

I am a comp sci major and I am trying to go to UCSC , UCI, or UCSD I am taking a non required course in hopes of getting into UCSB, but it is just too difficult and I am thinking UCSB wouldn't accept me anyways. What are my options? If I continue through the course will it matter if I drop for a W either before or after any admission decisions? I don't really want to drop for a W before my admission decision, because wont they look at that and think bad about it? Or will it 100% not matter?