I must be missing something here?? are you guys using ZFX? with the Z2 and Z5 I can detail my M5 in less than 3 hrs with multiple coats of Z2 and Z5 and that includes claying the car (no pressure on the paint either) and also washing. the wait time is 30 mins.. in other words, by the time you finish the whole car.. it's time to use some Z6 on the microfiber towel to wipe off the front.. so backache and arm-ache shouldn't really be... you should not be apply a lot of pressure either??? I must be confused..