tarpin it.

I'm not sure what type of temps you will be dealing with, but the first thing that comes to mind is that blue pad isn't going to keep you warm down to the 20F that the golite bag is rated to. There has been plenty of talk about this over the past month (I guess cuz winter is just around the corner) – check out some of the threads and you'll see most people, including myself, have beefed up the ground padding to save weight on upper insulation.
As for "bang for the buck" – check out the Montbell bags. They always seem to be coming in at good prices (especially with the helping hand of some of the overseas members)and everyone seems to be very pleased with them. For comparison, my winter bag is a Western Mountaineering Versalite, and I can't say enough good things about it.
HTH
Steve

Extreme lows may get into the teens. Very rare to see single digits in the South east. What would you recomend for ground protection. right now I use a Golite ground tarp then a Blue pad, then I would have my bivy. Is their a nicer option that is close in weight.

Tommy

For quality ground insulation, look at GossamerGear.com. Even the 1/8 inch pad has better insulation than the mass-market blue pads. You may need to experiment with the 1/8, the 1/4, and the 3/8 versions to find what works for you. They're certainly an economical investment to experiment with.

Is thicker better in this case? my blue pad cut down to torso length is 8.9oz with holding strap.

3/8" has a weight between 5.3 and 5.7 oz

for 20 bucks that is some good weight shedding. Does it insulate better?
http://www.gossamergear.com/cgi-bin/gossamergear/order.html

Tommy

Ditto on Kathleens suggestions.
Check out the thread link below – great info in there, or search for some of the other threads on cold weather sleeping pads. I'm not sure what temp you have slept in with that blue pad (I can't imagine very low, comfortably), but basically, the cold ground will suck the heat out of you – I found out hard way.
When you sport more ground insulation, you can actually get away with a lighter weight bag.
Again, for comparison, if it were low teens which I think is about -10C or so, I would bring my Down Mat 7 Short..which is a stone compared to your blue pad….but it is warm…read the link, you'll see why.

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/9862/index.html?skip_to_post=71420#71420

or search "sleep mat systems" and "winter sleeping pad"

Tommy, the weight of your blue pad just earned it a first class ticket to the garbagio my friend.
My GG thinlight @ 1.85oz. and my Montbell 90 @ 9.8oz. would bring you in at 11.65oz.

This setup is well worth the weight penalty of 3oz.

Steve

Yes, thicker is better, up to a point. After a certain thickness, any more thickness won't help. But I don't know where the point of not being better is. Since there is also a perceived level of warmth, more than likely it's different for each person. One option is to get a 1/8 pad and a 1/4 pad and use them separately or in combination, depending on the season – a 1/8 for summer weight, a 1/4 for shoulder season thickness, and combined, a winter weight. I use the 3/8 all the time because I'm a really cold sleeper. I may try the 1/8 with my new Big Agnes insulated torso-length inflatable pad, but my guess is I'll still need the 3/8 with it. The Gossamer Gear pads are for insulation, and the Big Agnes is for cushiness.

I was looking at the 3/8" for year round use. But I am interested in the Montbell 90 setup mentioned.

Will my Bivy provide any noticeable warmth?

Tommy

Kathleen: I seriously doubt the 1/8th inch thinlight provides more insulation than the "mass market blue foam pads." These blue foam pads are 3/8ths of an inch thick. While the thinlight pads "may" provide more insulation for a given thickness, to think that a closed cell foam pad 3 times thicker will provide less insulation is ridiculous. The main difference is that the thinlights are much lighter.

Warmth is subjective. YMMV

Thermal resistance is not subjective.

Either way it is lighter than my blue mat, so it would be a great investment in my eyes just for the weight loss.

Right now I am looking at
Poncho tarp and Silline 11oz
Ground tarp 3oz
Golite Feather 28oz
MLD Bivy 6.6 oz
GG 3/8 pad 5.7oz
TOTAL 54.3oz give or take some grams. That is lighter than my dual Sarguao slumberjack setup with out anything else added.
I plan on running this all winter here in the southeast.

Does that sound like a better setup? What temp should I be comfortable at? I know that my clothes add to that, but what would be a good ballpark.

Right on! that's what it is all about. I would still recommend going with more ground insulation. A warm bag doesn't really matter much if you don't have enough ground insulation. Have you considered the GG nightlight? It will be more comfortable than their 3/8 inch pad. It is 8 oz. for a 59 inch length. I cut mine down to 48 inches for a weight of about 6 1/2 oz. It has an R-value of 2.27 versus 1.42 for the 3/8 thinlight. More comfort and more insulation for an extra oz., worth it in my opinion. I still wouldn't take it down into the teens though. Adding a thinlight would allow you to do this though. For my feet I use my pack, a GoLite Gust with their padding removed and replaced with a piece of an old 5/8 inch ridge rest. The ridge rest has a R-value of about 2.6 (I think). I mainly did this for a stiffer backpanel, though the extra insulation is nice. The weight penalty is about 1/2 ounce. As for a temperature rating for your setup, Kathleen is right about warmth being subjective. I find that most temp ratings for bags are not really comfort ratings but rather you will not freeze to death ratings(My brother claims that marmot bags are actual comfort ratings). I don't have experience with Go Lite bags, but would recommend you use loft to compare bags, not their ratings. Anyway, with proper ground insulation and clothing insulation if need be, you could "probably" take a 20 degree bag to 20 degrees or a bit less. I would suggest using your setup in your backyard or wherever to test it out before trusting it in the backcountry. Cheers, Jeff