Viton will really stand up to a lot of heatit also doesn't mind being run dry once in awhile the rubber overtime gets hard brittle in cracks I would definitely choose Viton over rubber any day
Got mine from pcarnut (Wedge Performance LLC) on ebag. Bought the retainer side seals too. So far, so good. I hate leaks so spending a few extra bucks was worth it - 'cause changing them later, isn't.