This is kind of like what is the best oil, two piece head gasket or one. To use gasket sealer or not? In my case when I rebuild the rear on my KZ I used a kit from Z1 if I recall correctly. Took mine apart because it was leaking and cleaned the cylinder body in my parts washer. The internal bore looked very nice and I decided to just leave it alone. If it would leaked then I was prepared to hone it, but there was no pitting or corrosion involved. Been about 6 months now and still no problems.
Rick H.
