I agree, i would find a B2 stepping if i bought an E6300/E6400.
Some people speculate the L2's use 10W less than the B2's at idle, stock. I don't know wether this is true but i'd say it sounds about right. The L2's package is inferior to the B2's, meaning that a higher voltage will be needed at high (over)clock frequencies compared to the B2's, maybe this is the reason for the higher temperatures although there is nothing intrinsic which would suggest this is so. By the way, this is why the E4300 doesn't clock as well as it should.