How to get the Angry Tiger in Saints Row IV

The Saints Row Wiki lists the cars in the game and sorts according to their speeds and categories.

From that source, the fastest cars are (info in parentheses are where/how to get them*):

• 2-person capacity cars
  • Attrazione
  • Wraith (Shaundi's "Under Pressure" side quest reward)
• 4-person capacity cars
  • Blade
  • Genkimobile (Kinzie’s "Gambit" side-quest reward)
  • Hammer
  • Infuego
  • Pacemaker
  • Peacemaker (driven by police)

If there is no unlock/reward info, then that means that the cars are either randomly parked or driven by NPCs. The 'unlockitall' cheat and the Additional Cheats mod (PC only) can also add many of those cars to your garage.

^{Source: Personal in-game experience; some info are from the cars' respective Saints Row Wiki articles.}

No, you can not switch shoulder when aiming. It is believed that because the character is right-handed and looking from the left would be weird. There should be an option to make the character left or right handed.