I tore down the engine today. The pistons were toast. In the areas where the detonation was occuring the upper ring was pounding so hard on the land that it displaced the lower land binding the 2nd ring in it's groove. The bores looked good with only minor scoring which could only be seen but not felt, otherwise it was still showing it's crosshatch. Not bad for a 200K mi turbo'd 103. The main bearings were all in very good shape. A few of the rod bearings were starting to go through the first few layers of the bearing. There doesn't appear to be any damage to the crankshaft journals. Now for the good news.... the 4-matic block (103.985) does have the machine work for the piston oilers. Once I was down to a bare block I tossed it into our industrial parts washer. After drying everything out I went ahead and tapped the 6 bolt holes that mount the piston oilers. On the fourth one the 6x1.00 tap broke off in the block. It took about an hour to fight the broken tap out. After I had all the threads cut I went ahead and drilled the 4mm feed holes into the main oil galley. I rigged up an adaptor to put air pressure on the galley to keep as much of the chips out as possible. Minus the broken tap it's not an hour of work to finish the machine work to install the oilers (on a bare block that is). I really believe that the oilers are key to preventing a reoccurance of piston related problems. I'm really happy to know that I can do it with factory parts.