my dh had has the respironics (REmastar auto M Series) with a nasal mask. It doesn't even make a sound while its runnning. It took dh a good 6 months to get used to wearing it though, so be ready for a long haul of complaining that its uncomfortable etc..

The machine has a humidifier, which dh uses during winter (otherwise water drips up his nose).

You definately need the cpap trial to get the right pressure etc otherwise it will be useless.

We went to the public sleep lab and they did it all there.

hope this helps.