Yea, my relocator has a different threaded insert to accept the z9 filters. I know z30 are the same size, but different thread to the z9.
Yea its like 4" diameter. I had a z411, but the dump scratched the paint off the filter as i put it on and it was touching the dump.
I believe the bigger the filter, the better. You get a little extra oil, a lot more filter capacity, less pressure drop across the filter.
And the filter flows more, allowing the filter to stay out of byass longer
