I just finally got around to installing my 555's today. I have t/28's in and out in the stock housing, greddy intercoolers and DP's, TP's and Borla catback. I do only have the single pop at the moment. I was looking for the best overall setting on my apexi. It was set at 1 bar and about a 65% duty cycle on factory injectors. I was looking for a few ideas on a good duty cycle. Thanks! and yes I have been searching the forum!