....Maybe I am worrying unnecessarily, only on week 4 of spider ownership!
I've owned 5 spiders, 3 x V6 & 2 x TS (technically 6, because I bought a V6 12v LHD spider of army son) and they al behave(d) differently on the temperature front, Some run colder at speed, never getting to 90, except in traffic, others seem to run between the 'tick' at 90 at speed and just over 90 at the slightest sign of traffic (fans kick in occasionally to hold at that temp). Also summer and winter running makes a difference. A duff termostat will definitely make it run cold most of the time.
Others on here swear their cars keep at 90 all of the time - either their thermostat is really in tip top condition, or they are only running around town. In my experience, they all run colder than 90 at speed in the winter
I managed to drive 130 miles home last week, with a hole in the radiator - luckily the temp stayed down near the 'tick' whilst driving at speed on dual carriageways/ motorways, which stopped the thermostat opening to send water to the rad. If that car was a 'hot runner' I doubt if I would have made it!!
So, as long as the fans cut in above 90 and keep it thereabouts, I would not worry!!