My JL chips aren't too bad, putting around town it'll load up a little bit if I am just idling for a long time, but that could also be due to the fuel pressure being cranked, and the cam/headwork.
I remember reading somewhere that 40's just have a tendency to be fat on the bottom end, and that it's very hard to tune it out of them.
Can't remember where though, maybe it'll come to me later...