Martin See: http://www.elecraft.com/order_form_parts.htm#K2%20Parts Other than the key click modification for $19, most 3000+ serial number kits will have all the new features. The issue of possibly saving $100 off the price of a new kit is something only you can decide. 73 Dave, G4AON K1 #1154, K2 #1892, K3???