Tapping M3 threads in SLM print

I need to have m3 threads in a piece I want to order for slm printing. I have read that it isnt recomended to model the threads to get them printed under M6 so for my m3 threads I have considered tapping them. How viable is to tap them? As stainless steel is a very hard material im worried i might have issues doing so. If not, which hole size should I go with?