I'm just into owning my first Mooney and I'm hearing that I need to replace my donuts.  The donuts appear to indicate a manufacturing date of April 1998 by the "4 98" on them.  That would make sense as I have a logbook entry on 8/21/98 (2563 tach hours ago) that says "landing gear shock discs (all)".  Before I spend a lot of money on doing this, are there conditions I should be aware of?  I did a bit of searching on the donut replacement and it sound like old donuts are often accompanied by prob