I was browsing around the LT1 forums the other day and I happened to read about the optical issues. I believe in 96 it was redesigned to vent better and didn't have the problem nearly as much. A lot of the guys are switching over to a individual coil and the LTCC set-up though.
http://fullthrottlespeed.com/itemdes...CC~eq~~Tp~.htm
I am not sure about the o-rings.