You don't need a Carrera 4 to have fun in the snow with a 911. 911's have GREAT traction with rwd and are an absolute blast with the proper tires. I only drove my old '69 911 a couple of times in the snow but it was memorable.
I've done multiple cross country trips in my Porsche 944 and it is a fantastic car in a bunch of ways, thus the reason I kept it and sold the 911. I've lived out of it for multiple weeks at a time and used it as a base camp for some backpacking and 14'er climbs in the San Juans. Its probably been on more 4wd only roads in CO then any other Porsche, haha. I could pack two mountain bikes and gear with carefull packing in the back and managed 30mpg on the highway. Any suffering with the cramp space was paid for 100fold on the twisty bits of road sampled along the way. 944's are some of the best handling cars ever built, though not the most powerful,
The purist in me says do the Elise, primarily because it is a proper sports car and is on the top of the list of dream sports cars for me. It will require sacrifice in packing and planning but good mpg, and nothing will be more fun in the twisties. Sure you could do that trip in an M5 with more comfort but there is no denying the same trip in an Elise would be WAY more memorable. Plus, that's the best autocross/track car off the showroom with the exception the 997 GT3 RS of course.
(my absolute dream car)
Anyway, heres my last road trip with the 944 from last spring, since I've stripped it of any creature comforts, ha ha
Here's me with it back in '95 just outside of Lake City, CO.
I had a couple of memorable fun road trip experiences last winter via fun cars.
Vermont last March with a Porsche 996 Carrera 2
And January in Germany, Austria, Switzerland, Italy, France, and Lichtenstein in an S line A6 avant TDI, absolutely transformed my perceptions of diesel and sporty.
You can tell I dig road tripping no matter what the method, haha.