Welcome from the crew at Livernois Motorsports! You've definitely picked a great board for the Explorers, tons of friendly and knowledgeable members on here.
Congrats on the new ST, I have to admit that is one of my personal favorites right now in the EcoBoost world in general. Ford going back to the longitudinal layout and being predominately a RWD type of AWD was an excellent choice in my opinion. These trucks are amazing already in stock form, but just our custom tuning alone and good fuel makes an even more incredible jump in performance and picks up a few MPG when you're taking it easy. We estimate over 500-560 HP at the engine which is phenomenal on these type of vehicles tune only. I've even seen some photos of one pulling the front tires off the ground at the track already. Feel free to give us a shout if there's anything we could help you with!