It depends on the DAC and connection. The "best" DAC renders the streamer irrelevant. IF you are using USB. If you have bought into IIS the streamer, and the cable are critical because they provide the timing.
If I had a $20,000 budget for a digital front end, $18,000 would be the DAC, $1,500 the streamer and $500 for the rest. Choosing a DAC where isolation was an important design consideration.
My own breakdown is (approx) $25,000 DAC, $3,000 Clock, $1,400 Streamer, $1,600 cables (include Cardas Clear Reflection Interconnect DAC->Pre). Nothing for connection as it uses WiFi (no alternative).