Cache + suggestions

[ElementShadow]

I download video from youtube to a disk D, but its still using disk C for temp download to convert on disk D. so problem is i dont have space on disk C for that and i cant finish download -_-) make option to change temp cache directory. Also would be good if i can choose video quality i need from video (bcs i dont understand what means "prefer video with this "quality choose" i dont even know what expect from download