Glad this thread has popped up as I have just fitted one to mine!

I've got the standard 14.7:1 at idle and 11.5 on boost but see some real lean numbers when on off throttle like 19:1 be it only for a second and also up to 9:1!!!
when I first start the car (cold start) it idles with an afr of 10.4:1 until it reaches temp, does this mean the cold start of the map needs to be adjusted?
also when its had a bit of a boot it will idle at around 15.2:1.
Is any of that anything to worry about?
cheers