why do I smell gas when my Subaru Legacy heats up from driving?

Is the car rusty at all? if so, could be a pinhole in the fuel tank. I would check up in the engine for pinhole or cracking in a soft line to the fuel filter or on either side of the engine.

any luck / findings?

Found a few loose connections around the fuel filter we replaced last year. Seems to have helped. Waiting for hot weather to see if it continues to work. Thanks for the tip.

Awesome. I've never heard of fuel weeping during the summer but I guess it's plausible. I've had fuel smell problems in the winter. It makes the lines shrink a bit and it's usually in those same areas and on the fuel rails, etc.