Silvia LinksThere's a lot of information out there for this excellent high-end consumer machine. I've sifted through a lot of them and list here those that I've found the most useful.
A Tail About Silvia - Adding a PID controller gooseneck style
Silvia Pressure Mod - How you could tweak the OPV to reduce pressure
Descaling Silvia - Thread on Home Barista forums
Silvia Backflushing - Backflusing (just do it in my opinion)
Sweet Maria's Silvia - It's a sale pitch, but shows the Silvia in detail
For generic coffee links see misc links.