i just did an m104 there are people who will tell you that you can leave everything on... and i suppose if you were a real expert ;you might be able to...

but from a guy who has done one... the only way i was able to do it was by removing everything....

secondly. if you removing the head you need to take it down to a machine shop and have it reworked... and if you dont remove everything the guy at the machineshop will had you a ratchet.... and say take that stuff off...
your waisting your time if you do not have the valve guides replaced, the head ground flat, and the valves reground.... anything less is a waist of time.. so since this is a requirement then you should go ahead and remove everything....

if you dont remove the intake then you must disconnect all the electrical and fuel... the electrical is very fragile and you will probably do more damage in
the long run by leaving the intake on....