I'm not sure what the issue is with your Mirage drive. Do you have pictures to illustrate the problem?
Regarding seat pegs not staying, do you have the newer expandable pegs? Here is a link to ACK showing these pegs. http://www.austinkayak.com/products/2293/Hobie-Seat-Peg-Kit.html?k=hobie%20seat%20peg
These expandable pegs hold quite well on both my wife's 2009 and my 2011 AI. Another trick is to glue some kitchen drawer non-slip material
on the bottom of the seat. The non-slip material can be found at "The Container Store." Here is a picture of material I have glued on the bottom of my seat. It will be cut to size and glued on.
Still, the expandable pegs work quite well by themselves.