If you had a seat lowered by Pirate, what year is your MP3 and did they need to modify the pan? If so, where was the space lost? They've told me that the seat was changed at some point and they can't remember whether it's the old or new design that requires modification.
On my GTS seat the space was sacrificed at the front in order to provide a horizontal surface. If this is the same on the MP3, I might still be able to fit my FF helmet in the rear of the compartment. (Despite all the posts from people who have been able to wrangle it into the trunk, I've been unable to find a way to do that.)