I would agree with Diablos, the K. Toccatta is not that difficult. It sounds a whole lot harder than what it is. Most people are not impressed when hearing that piece, if they have studied it.
Grandados, would be good. How about Malagueña, by Lecuana. I mispelled his name. I mean the advanced version. Very impressive, a little more technique though, yet it is great once you learn it. This is one of the few pieces I can remember I enjoyed the whole process of learning it.
Well, see you later, and have an nice day.