I'm all for customization, and not worrying would someone else might say based on aesthetics. However, I have to agree with oldacura - the bored out rear stem is very worrying. I would have kept the stem you like as it was, then found a seat post that fitted the stem without any modification, then used a shim to make the new seat post fit in the frame correctly. Anyway, enjoy the riding, it can be even more enjoyable when you have it dialed in just right for you both.