I pierced the foam of my yellow cart 400x to test this. No problems so far.
I'm still using my first set of cartridges (which came with my printer 2 years ago) without problems, using the Durchstich method and Inktec ink (but I guess every quality ink will do).
I'm still using my first set of cartridges (which came with my printer 2 years ago) without problems, using the Durchstich method and Inktec ink (but I guess every quality ink will do).