I’m off to the Nurburgring in my non-air conditioned S1 Exige at the end of July. If the temperature is anything like it has been this week I will probably be driving naked by the time I arrive! Still, if it’s dry I refuse to complain about the heat
My main concern about using an S1 Exige for two people on a European tour is the lack of luggage space. It doesn’t really have a boot, just a shelf behind the engine and the access to it is largely obstructed by the air box. My Caterham R300 had more practical luggage space - definitely a case of check before you buy.
I’ve done two-up camping for 8 days in an S1 to Le Mans.
You need to use ‘squishy’ bags in the ‘boot’. If you pack into small bags, it’s amazing how much you can get in there. T -shirts and trousers that zip off at the knee and a lightweight waterproof cover most aspects of summer weather needs. Don’t forget storage space under the passengers knees (unless you have an extinguisher there, of course) or in the cargo net behind the seats. Use modern camping towels (a bit like a chamois leather but for people rather than cars).
Some people put a largish but empty bag in the boot before filling it with smaller packs and this seems to work well at keeping all the small packs together. If you are taking a helmet this will use up quite a lot of space so use it as a container for socks, underpants, that sort of thing.
Give my best to Rob and Ben.