Yep this arrangement is very standard on MRL lifts, particularly car doors that are pretty flimsy. We had a stock standard procedure that worked, ie worker in the pit, who unhooks the bottom bolts- then the worker on top of the car cuts the ties to the leads to the units, so they can be raised up onto the car and then subsequently replaced- then new units lowered and bolted down to the sill once again. Some come with a frame, that has to be switched, others don't. Most of the time you can swap with a commercial unit ie pana40 but remember to match the pnp/npn units or they will work in the reverse.