My VX also gets to 100c on hot days, did one long run to Le Mans when it as was at that level for a long time. it was worse when I first acquired it about 13 years ago but changing to a new radtec aluminium radiator helped and I have the larger dia fan that they do. I think I may also have installed a thermostat that opens at a lower temp but I am not certain about that as it was 10+ years ago i have mechanical gauges and water temp is nearly always higher than water temp, I am tempted to fit a laminova to balance the temps but I don't think it's essential. if you don't have one it worth getting a heat shield between the exhaust and the alternator - on long run to Le Mans the engine was fine but I discovered the alternator was cooked when I got home. More recently and for other reasons I had the engine rebuilt and it generally runs cooler now but will still be close to 100 on hot days - we have done some long runs in very high temps across France and Spain. Worth checking everything is working correctly but not sure you should be too worried, that said I would recommend getting good mechanical gauges for water temp and oil temp/pressure