[mike f]

There are several variables which need to be considered here. I assume that by a storage lift you are talking about a 4 post unit. A "typical" Bend Pak unit is about 8' tall. Lift is about 6' from the ramps, which are about 5" or so off the floor. Is the Porsche the only car you will be putting up on the lift? Obviously if you put a Navigator up there you will need significantly more headroom.. Another thing to consider is if there are going to be any lighting fixtures installed over the lift. Is the garage door going to be an overhead unit or the "barn door" type?

I would say that since this is a new construction, give yourself plenty of room to allow for any possible scenario.