I just ordered my gauges for mine. I'll tell you what I have done so far. By the way, I do agree it is a very nice piece and fits great.
For the part of the dash that goes down toward the center consol, I removed the stock supports from the stock dash, removed about 2 or 3 spot welds on each side and then used rivets and epoxy to mount this piece to the PDK dash. This allows for a mounting point from the PDK dash to the stock mounting point on the tranny tunnnel near the fuse box.
From the mounting points on the PDK dash on the far left and rioght lower corners of the dash, I drilled holes in the dahs and used nut, bolts and washers to mount the PDK dash to the stock dash mounting points that are near the air vent pulls. Use the washers to make sure the dash is sandwiched and not tightend down on a surface that is not perfectly flat.
For the mounting points at the leading edge on the top of the PDK dash, I made 5 brackets out of 1.5 inch wide aluminum that bolt to the stock dash mounting points just under the wind shield. Holes are drilled in the dash and thru the bracket and secured with nuts, bolts and washers.
Hope that helps. I could have made the console area brackets out of aluminum strips also but the stock parts were already bent correctly and easier for me to use them. I would take some pics but my son has the camera and has been to New Zealand and Australia. He'll be home soon so I could post pics if needed.
Mark