thats would have been my first guess.. considering that it took a couple EFI fuses before the pump died... pump on its way out probably was drawing tons of current just before the fuse blew..replace the fuse, pump heats up again... fails again, blows the fuse... now the pump is dead.... no...
im assuming you dont have power seats? will any amp fit if you have power seats.. thats one of the things id like to find out before i venture into installing an amp..