It can sometimes be useful to quickly pass under an obstacle which otherwise requires crouching, like a low and narrow bridge when you run in a creek bed or a tree log laying over a path.
Just remember that after the slide, your character is in the crouched state, so in order to not lose the valuable milliseconds you just gained, immediately press sprint again to get back into the sprint state.
Here are the quotes:
"In another moment down went Alice after it, never once considering how
in the world she was to get out again."
"'I like the Walrus best,' said Alice: 'because you see he was a LITTLE
sorry for the poor oysters.'
'He ate more than the Carpenter, though,' said Tweedledee."
"'Oh, you can't help that,' said the Cat: 'we're all mad here. I'm mad.
You're mad.'
'How do you know I'm mad?' said Alice.
'You must be,' said the Cat, 'or you wouldn't have come here.'"
"'Have you guessed the riddle yet?' the Hatter said, turning to Alice
again.
'No, I give it up,' Alice replied: 'what's the answer?'
'I haven't the slightest idea,' said the Hatter."
"'What do you mean by that?' said the Caterpillar sternly. 'Explain
yourself!'
'I can't explain MYSELF, I'm afraid, sir' said Alice, 'because I'm not
myself, you see.'
'I don't see,' said the Caterpillar."
"'Everything's got a moral, if only
you can find it.'"
In the "If only you can find it" part, the words "kill", "fuck" and "find" are shown alternately until settling at "find" in the end.
The screen captures are from this Youtube video:
I got the text from Project Gutenberg:
Alice's Adventures in Wonderland by Lewis Carroll
Through the Looking-Glass by Lewis Carroll
All quotes are originally from Alice's Adventures in Wonderland, except the second quote ("I like the Walrus best.."), which is from Through the Looking-Glass, and What Alice Found There.
Best Answer
Signature weapons are version of normally available weapons with pre-installed mods and custom paint jobs. Each of the base weapons is or will be available separately in the store, not necessarily before his "signature" counterpart (Specifically, the Vektor is available late game, I unlocked most signature counterparts before their "normal" versions).
You can check what criteria is needed for signature weapons by checking your hand book, they appear in the game progress summary page as stars (check the legend at the bottom), or this handy list (copied from here):
The weapons will always have the same mods/color scheme, regardless of play style. Three of the signature weapons - Shadow, Shredder & Bushman - have suppressors; three weapons have red paint jobs - Shredder, Ripper & AMR. I'd double check your facts, because of those only the Shredder is both red & suppressed (AMR is anti-suppressed, TBH...).