Sorry, should be been clearer. AFR is instantaneously hitting the lean end of the scale at 21.
Its running 550cc injectors, Uprev MAF and custom map, fuel return system, platinum plugs, walbro pump, plenum spacer and stainless exhaust with sports cats.
I had a leak from the supercharger output shaft which wasn't too bad so didn't clean it the first time I resealed it but cleaned it today with a good dose of brake cleaner for good measure which hasn't seemed to help.