In both habitats, Darlingtonia experiences similarly high temperatures during Summer months. One site in California, near the Oregon border and even within sight of the coast was well over 39˚C (102˚F) when last I saw it in July 2004. Theoretically, the alpine form is just a bit more forgiving of those Tbs; but I've noticed no real difference under cultivation.
Again, it is primarily a matter of keeping the roots reasonably cool; provided that that can be arranged, the vegetation itself can withstand far greater Tbs. A large pot -- preferably terracotta -- frequently watered, with an airy open compost of live sphagnum, pumice and perlite will offer sufficient volume and aeration to offset any Summer heat . . .
I gave a friend in Austin, Texas -- no stranger to heat extremes -- a number of coastal Darlingtonia some years ago; and they are flourishing under his care, a few planted in terracotta pots and some in a bog garden in his backyard.
I believe that the whole distinction between alpine and coastal forms of Darlingtonia is spurious, and is more an effort at marketing than anything else . . .