Have you ever researched the absurd power and torque figures of a modern diesel pickup? Many of them make 400+hp and 800+++ lb-ft of torque, bone stock. (And many of the older ones are only a plug-in tuner and some very cheap mods away from making similarly absurd amounts of power/torque). Yes those trucks are big and heavy, but that's a LOT of torque and power. I wouldn't be surprised to see a dualy leave an ecoboost Mustang in the dust for a short stretch at lower speeds.
As for the Rio, I don't know what to tell you there. Your car should be significantly faster than a Rio (a couple of seconds faster through a 1/4 mile if you're comparing documented performance figures), but that 2 second difference assumes the Mustang doesn't spin the tires and is being driven at wide open throttle and shifted at/near redline in every gear etc., - if the Mustang driver was short shifting and/or got a craptastic start/spun the tires off the line etc., while the Rio got a perfect launch and just held it to the floor the whole time, it could take the Mustang a while to reel the Rio in.