I had no luck with plyers, I found most wouldn't close all the way around, I did find a way to make the snaps hold better with the tools supplied and a screwdriver http://www.whitearmor.net/forum/topic/28934-howto-make-snaps-hold/
Nice work so far, I found using a sliver based paint really helps to fill in left over lines in 3D printed parts, just apply a few thick coats allowing tor dry in between, easy to sand too.
Love a BBB, as Caleb said Spec Ops look after the Shadow Trooper, you may want to head over there. Here's the CRl http://databank.501st.com/databank/Costuming:TX_shadow_stormtrooper
Says item no longer available so I think that answers the question .
eBay or as we call it evilbay is a very big miss for armor, you can from time to time find the odd accessory but really stay away and use these forums
I use a similar tip to your second image but it is rounded on the end and seems to get into the corners quite well.
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For the cutting disc I use a thin diamond disc, works great with ABS and doesn't melt as much as other cutting discs do.
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