Fixed Air control
More movement in the air. Downside cannot crouch and doesn't work while holding a medium mission item.
Ambi dex
Can use your secondary weapon while holding a medium item. Downside is much lower accuracy and bigger bloom.
Thief
You can break into an opponents car. Takes longer than npc cars. Needs some other downsides as well
From cars I wish a 4 slotted 4x4 Calabria, faster acceleration and top speed, still not near as fast as a Vegas, but amazing at dodging rockets and it's free to spawn.