Our PSA: do not use a sender with a plastic float. We wish suppliers world-over would stop supplying these plastic floats, as we keep running into problems. They are useless, and will sink within their first year in ethanol. Our brass float solution is impervious to ethanol, unless you want to change your sender twice, you need to use a brass float.
The other weak spot with senders has been the cork gaskets that both seal the unit internals and the gasket that seals the sender to the tank. Our kit comes with a viton set of gaskets.