I would get a two post, but not for storing a car.
I think if you want to store a car up in the air you get a 4 post - if you want to work on a car, you get a 2 post.
03 Z06 - Cyber Grey - H/C/I/E - 466rwhp/416rwtq - Rear Widebody, CCWs, Coilovers, lots more
99 Trans Am - Cam + Bolt Ons 412 rwhp / 418rwtq - Sold
94 Formula - Bolt Ons - Sold