Opened up the box containing the exhaust from Lancair today. What is 
the purpose of the two exhaust clamps which have a pin welded to the 
inside center? Are they used to clamp the tail pipes? Do the 
crossover joints get clamped or remain a slip fit?

Angier,

 

The crossover slip joints are just that, no clamps.  It is advisable to use an anti-seize (Permatex hi temp) on those joints as they move quite a bit.

 

After the exhaust is mounted, slip on the tail pipes and move them about with the cowl in place - when you are happy with their orientation, drill a hole through the overlap of the exhaust and tail pipes for the clamp pin.  Make sure you carefully locate where that hole is placed since the clamp is held in place with a drilled bolt and castle nut because of the hi temps.  In other words, make sure the clamps don't clash with each other.