Remove the swivel seal and let grease drip out. Refit seal and fill with new grease. Make sure to turn the wheels so new grease passes the goes into the swivel and not on top of it.
I’d say the boost pin makes more difference,
It’s like most tuning things, it’s a game of diminishing returns. I’ve a turner performance head with turbo technics vnt turbo, so the extra fuelling is required to get the best from the other mods...