I have a 2 post, and cannot see how I could do some stuff at all or without difficulty on a 4 post. Very little of what I've done needs a 4 post. One exception is stuff like U joint angles or front end alignment. For front end stuff I block up the trailer level with the car on it, and use the trailer itself for a 'front end rack" Of course this is alignment only, you would not normally use that (at least my age) to replace parts
