well I suppose it depends on the climate you live in.
I live on the north west coast so its a wet climate half the year and usually not more then 80 or 90 in the summer but not dusty so the filtering limits of the K&N aren't a concern for me. However if you lived in a real dusty dirty climate there might be a better one out there. I think K&N's rateing is 95% or so.
As far as EGT goes if I understand what I have read when you go into regen it goes up for the cycle. I don't see how lowering your average daily egt would affect it I would think it would still go up to the temp needed for the regen cycle.