On the B18C1/B18C5, the cylinder pressure must not exceed 270psi or be any lower than 135psi.
There must not be any variation greater than 28psi between any cylinders.

You can perform the test on a cold or warm engine, but a cold engine will yield lower results.

An average of 165 sounds a little low to me; my GSR was in the 180's at 160k miles.

How-to's:

Compression Test

Leak-Down Test