...honestly, it's not bad driving in the fourties at all, and certainly doesn't require bundling up like the photograph...once temperatures hit the mid-thirties, you'll need the heater blowing on your hands to keep them from going numb, but other than that, a t-shirt and jeans with a sweatshirt on top are sufficiently comfortable for hours of driving at speed, and a cap's not a bad idea, either...i can't speak to driving topless in the twenties because i took advantage of the rare opportunity to use my hardtop, though...
...the greatest challenge with cold-weather driving i've found to be keeping the engine up at temperature: in the low-thirties i'd lose my second cam shortly into any high-speed blast and wouldn't regain it until several minutes of cruising back down at more civilian speeds, and in the mid-twenties i'd loose temperature readings altogether when cruising much above eighty, in fact i never warmed up enough to push redline north of six thousand...