Taylormade's TP (Tour Prefered) clubs are aimed at better players, so differ slightly in design to non-TP ones (1* open clubface instead of closed, higher CG for lower ball flight, better quality TP Rombax shaft, supplied with 6 movable weights instead of just 4, etc). Essentially they are meant to be the same as used on tour, although Pros will likely get them hand-picked (tested for COR, loft, etc) and custom made to their specs so the shaft and weighting might differ.
The better shaft and more weights might add some cost. But manufacturers like to put a premium on 'tour' equipment. Maybe not produced in such large quantities so cost more to make? To suggest it is that much better, or that they know better players are willing to pay more?
