Tuning suggestions wanted

I'm looking for suggestions on tuning Solaris 9 for a SunFire 890 (Ultra
IV chips) connected to an Hitachi 9500V running PostgreSQL 7.4.

So that I don't lead people in a direction, I'll hold off for a while
before posting our configuration settings.

Database is approx 160GB in size with a churn of around 4GB per day (2
GB updated, 2GB inserted, very little removed). It's a mixture of OLTP
and reporting.

5% is reports which do trickle writes
95% is short (30 second or less) transactions with about 10 selects, 10
writes (inserts, updates, deletes all mixed in) affecting 150 tuples.

Thanks for any tips -- particularly Solaris kernel tuning.
--
Rod Taylor <rbt(at)sitesell(dot)com>