[6pack] Question re: cracks in IRS trailing arms

[Chuck Arnold and/or Kathleen Kelley]

Both of the trailing arms on my TR6 racer have cracks in the trailing arms.
They are about 1 to 1.5 inches long and start at the bottom edge immediately
in front of the brake backing plate.  They go through, that is are visable
from both sides [though worse from inside].

Questions:
1. How dangerous is this?  It looks like there would need to be a whole lot
more cracking before danger of breaking.
2. Can they be repaired?
3. Can I do a lapping day practice in a couple of weeks with them in this
condition [may have been like that for a long time?].

Thanks in advance,

-- 
Chuck Arnold