Hi ALekzc...... Welcome to the Forum
I saw your emitter question answered in the Questions thread, I'd just like to add that emitters can only be changed on saber models that have MHS compatible emitters....
The switches are a little more difficult..... A quick question, does your saber have sound?
Sabers with sound use a momentary switch and stunt sabers use a latching switch.....
There is a bit of information on switches here
http://www.saberforum.com/index.php?topic=24480.msg369046#msg369046 so you can understand some of the details..... but, Yes, you can buy 12mm or 16mm momentary av switches, you will need to remove the wiring, drill out the switch hole and re wire..... If you have a saber with sound you may need to add wiring to the board to install an illuminated av..... there are wiring diagrams to help.....
If you have a stunt saber, again you can buy 12mm latching av switches that have the correct length to fit, you still need to drill out the switch hole..... Some 16mm latching av switches are too long to fit in an US or MHS hilt, and if you want to put a momentary switch in (the shorter ones) you need to install a momentary to latching converter for a stunt saber, also drilling out the switch hole with a 16mm drill bit.....
Hope that starts to answer your question..... let us know if you want any more info..... cheers