I bought in bulk from eastmall ... I'm also just tired of drilling holes and killing 2 out of 5 cartos doing it ... And tired of pulling the stickers off and trying to make it glue free...Are you using high quality cartos? Are you testing them before drilling them? And after? Testing twice can tell you if you disrupted the design of the carto while drilling. I see minor performance fluctuation when using hq cartos, when I try to get away with el-cheapo's I regret it.