4 pair of MX3 ! You need to start saving money for the kid's college tuition. I wear the IS and don't find them overly stiff, but I was coming from Vapor apx (grotesquely stiff). If you are concerned about stiffness, I think a good choice is the SMU Bauer Ignite, a combination of the 180/190/ and IS at a fraction of the cost of the 1S.