3 lb DME, 8 oz (Bairds?) Carastan in 2 gal water reads like a maltier IPA with OG in the 65 range. If you don't like maltier/"sweeter" beers, this may not be a good "grain bill" for you.
2 lb DME, 4 oz sugar (10% of fermentables), 4 oz Carastan is closer to a classic APA (OG 50, FG 9, caramel / toffee notes).
edit (for future readers): see also this: https://www.homebrewtalk.com/forum/threads/is-dme-only-brewing-a-good-idea.455223/#post-8657757
In 2019, "No-boil DME" is definitely a trending topic.
But "15 minute Pale Ale" (links below) remains an interesting process option. A 15 minute boil will have more "traditional" bitterness than a "no-boil" (hop steep or "hop sampler") approach. Steeping the crystal/caramel/roasted malts starting at flame-on and removing them when the water gets to around 170* F will save 20 - 30 minutes in the brew day. First wort hopping (remove steeping grains when water gets to 170* F, add DME and hops, then proceed to boil) would also be an interesting option.
Between "no-boil" and "15 minute pale ale", there is the BBR "Hop Sampler" process. An overview of the process is to 1) bring the wort to a boil, 2) add the hops, 3) remove the kettle from the heat, and 4) let it sit for around 30 minutes. You will get some traditional bitterness and there is no need to control wort temperature.
With a no-boil approach, wort temperature matters: for me, 180* F (or above) yields results in some "traditional" bitterness (which I like). Below 180* is generally "uncharted" territory for me (for the few NEIPAs that I have enjoyed, I found that I like some "traditional" bitterness my beers).
links:
http://beerandwinejournal.com/15-minute-pale-ale/ . See
https://old.reddit.com/r/Homebrewin...ve_any_luck_with_an_all_extract_wort/djwjf8x/ for ideas on style variations. And don't forget about Munich and Vienna DME (new as of late 2015).
http://www.bairds-malt.co.uk/Bairds-Malt/Technical/bairds-malt-technical-malt-analysis
http://www.basicbrewing.com/index.php?page=radio for podcasts of BBR "hop sampler"
http://www.bairds-malt.co.uk/Bairds-Malt/Technical/bairds-malt-technical-malt-analysis