^I think you mean Vobsub? To view subtitles, I recommend just getting GOM player, because GOM player can play anything and it automatically can load subtitles (either by i.) clicking and dragging the sub or ii.) renaming the sub and the file with the same name) without dling anything extra.
HQ = high quality
LQ = low quality
HQ episodes are usually 700mb whereas LQ episodes are around 150mb. Subtitles are usually timed to HQ episodes, so when you use them for LQ episodes, they are sort of off. However, with GOM player, you don't need the different subs because you can adjust them yourself.