All of the hush kits that I've seen (FedEx, Quiet Wing and Valsan) got rid of flaps 40 in the mid 90s to meet Stage III noise standards...
True statement... part of the STC requirement... also for Raisbeck. However with the Raisbeck kit, the LEDs were restricted from their full extended position, thus resulting in, for a lack of a better term, improved climb, and approach climb performance. It also resulted in greater weight penalties too over the FedEx hush kit. Raisbeck equals smoke and mirrors.