A standard Wii ROM dump (in WBFS or ISO format) is a 1:1 copy of the original disc. An "Extra Quality" version suggests a —one that has been stripped of region locking or modified to remove "laggy" intro videos.

a specific type of file dump or a modified version intended to improve the base game's performance or visual presentation

file is all you need; the "quality" comes from your emulator settings and texture mods! to unlock the framerate or adjust the for your setup?