I finally got the NX-250 on Friday, and the suspension was already converted to whoopies. (I love them) I also have the Z-Liner insulation. I hung friday night in it with the Z-Liner and a 0 degree sleeping bag. It got down to the low 30's and I was toasty warm. I don't like sleeping bags so the next time I plan to try a TQ and lay on a poncho liner just to add some cushioning and warmth under me. The Z-Liner did well, but in the low 30's I needed a little more. I think a poncho liner will do the trick.