If you have a composite fuel tank and the fuel available in your area
has ethanol in it then you should google something like the
following...

ethanol fiberglass fuel tanks

There you will find out that the ethanol content appears to be a
significant player in relatively rapid deterioration of the resin and
therefore early failure of the fuel tank

Looks like the boaters have been seriously affected by the E10
situation and if your motorized sailplane also has a composite tank it
may be at risk of early failure.

AVGAS probably doesn't have Ethanol added so if you have a composite
fuel tank, it may be very wise to only use AVGAS even if autogas w/ 2
cycle mix is allowed.