You can get there digitally or in a darkroom, here at APUG we only discuss the traditional processes, no digital. See DPUG.org or one of the many other sites that deal with photoshop for digital questions.

Having to underexpose with a color neg says to me that the guy or gal printing you negs needs some management. Ask them to print it darker.

I regularly overexpose color negs by 2-4 stops and still get nice, not washed out, prints.