Hi, I found some pictures of a project where someone changed stud numbers and PCD by welding and redrilling. In this case it was turning a Mazda RX7 five stud hub to a 4 stud Mazda MX5. It involved welding up the holes and the irregularities on the RX7 hub (they aren't circular - in order to save weight). New holes were drilled and the whole lot turned on a lathe: