Actually, I was rather disappointed in the blue inserts myself, though for a different reason than anyone else has posted. My cab is a refurbished Mortal Kombat, with its original door still intact, and the Happ blue inserts didn't fit the door. Even if they had fit the hole, there was clearly a problem: the original red inserts (which I still use, despite the fact that my cab is painted blue) had a coin slot in them, and these don't.
But if you have a Happ door already, I'll wager they'll do you just fine.
-E