MH Synthetic fill 20* liner

[saimyoji]

I have the MH X-country 40* bag. Its way warm for me, but I'm looking to upgrade to a system to use on colder nights.

I'm considering adding the MH Polarguard 3D liner to be comfortable on colder nights. Does anyone have any experience using a system like this? THey claim it will add 20*. Will it really?

I'm also considering adding the expander to give myself a little more room.

Question: Does the liner zip into the sleeping bag, or is it a self contained bag w/in the bag? Will the expander make any difference if the answer to the former is the latter?

I'm leaning this way because its on sale at Campmor now, and I don't have the budget to buy a new bag. I do own a 10 yr old Thermolite Extreme bag (40*) that I could just use with the MH bag. I assume this would effectively be the same as adding the liner? What about just draping the TE bag over me inside the MH bag w/expander, like as a quilt? Would that help at all?

I have relatively little experience in cold weather backpacking. Car camping, yes, but not solo in the woods.

On colder nights I sleep in thermals, no socks as they make me feel claustraphobic, my tent is a Eureka Timberlite 2.

Comments? Suggestions? Please no hammock remarks. ;)

[briarpatch]

I have one of the MH polarguard liner bags from 6-7 years ago. Unless the design has changed, it has a double set of zippers. The inside zipper lets you zip it into another bag, and the outer zipper is used to zip the bag shut. I've used it stand alone down to about 45 degrees, and used it as a liner in a North Face 30 degree bag down to about 15-20 degrees.

(and I've used it open as a summer weight top quilt in a hammock :D )