Pinion Snubber + Sportlines... a must?

is the pinion snubber needed at all? i know there was some discussion about it, but i really don't even know what it does.

i took it off when i took off my dogbone with the stock springs... but now i put sportlines on and don't know if i should pick up one of the adjustable ones or something

there's some grinding i hear, but i'm not sure what it is.. haven't got it back in the air since the install saturday