Have you considered second hand?
Find great deals on eBay for synthetic sleeping bag. Shop with confidence.
www.ebay.co.uk
I don't know about the exact bags that you list. My first bag, in 2003 was a Softie 6 Kestrel which was not really warm enough for under a tarp or in a hammock outside late spring - early autumn. I took the logical step of getting a Softie 10 Harrier, which I found okay, but still could be cold in early winter/early spring tarp/hammock conditions, probably more to do with my under-insulation than the bag itself. I didn't like the weight and bulk so eventually sold it and bought a Marmot Helium, followed by a down quilt.
The Snugpak bags were okay. I cannot think of anything that made me think they were great, nor anything that stands out as terrible. Looking at the Sungpak military site, its hard to see any significant difference between the Softie 9 and Elite 3, so I think my Softie experience is probably representative of what to expect from the Elite.
The Intrepid 1000 is rated as comfort to +5C while the Elite 3 is rated comfort to -5C, with a 640g mass penalty and larger packed size. Since my experience has been that rated comfort temperatures are always a bit optimistic for my use. They are generally arrived at for two people sharing a tent, while I am solo under a tarp, which is a lot cooler. So for that, the Intrepid would be a two season bag at best, late spring to early autumn, say a night time low of +10C.
Do you plan to use the bag in a tent, no drafts, with someone else to help warm the space, or are you thinking solo tarp/bivi camping? Do you think you will be camped in places the wind blows, or its hard to get shelter?
All the best, and good luck!
Chris