iv bought a tange hotheart am gonna give it a miss in drilling the heart out, its easy and possible, the hole on kuwahara is slightly bigger than 1p and its 22mm. its easy to drill it out but i just rather keep the heart as there is more ET kuwahara than the heart frame itself. if you wanna drill it out to make a replica thats grand but if you wanna sell it on just make sure you say it isnt a genuine ET frame