It's one of my favorites, it truly connects you to a higher energy. I did 31 mins/day for 40 days recently. Loved it.

I used the mantra on Gurunam's CD "Seal of Higher Destiny" to help pull me along. His version is exactly 31 minutes and it really helped me pace myself and focus on my breathing.

I also did a 2½ hour version of this about 6 months ago during a seminar, and having the entire group chanting together really helped to amplify the energy.

Sat Naam. I have recently completed my teacher training and we did this for 2 1/2h before our exam as morning Sadhana- it wasn't something I thought woulld take me as the normal 11min dries my throat out. However it was one of the most beautiful experiences I have had, the time just flew by and I could of continued it all day. As with all mantras alot of the technique resides in the pronounciation and the tounges relastionship with the upper palet (roof of mouth) to stimulate meridian points. this maybe something you have a quick look at before begining to get the full effect of the meditation.
Hope this helps.

Siri Shiva Kaur.x