if u do it correctly this will not happen, i had a metal "dose" pipe made for my 34, i removed all the piping for it from above the turbo (sorry i dont know the mechanical name but it was 1 black pipe and 1 steel/alloy pipe" and also blocked out the bov and i never stalled. as for backfiring after i installed my cooler i got backfire a lil bit and i didnt realise an increase
i run a hks ssqv now though so no more dose as i got a bit over it