What if Drift crash lands on earth near where Mark Wahlberg's characters' home and scans the Sonic RS that is being worked on for Jack Reynor's character?
Perhaps Drift escaped a Decepticon ship or something and is trying to warn Optimus & his team of an impending attack (China?).
Now, why would NEST team and the Government be chasing the Sonic RS w/ Marky Mark & his funky bunch inside?
I think that (like in the IDW Comics) Drift is a former Decepticon who changed sides. He's being chased cause the energon detectors (From Dark of the Moon) picked up a Decepticon presence. Everyone rushes in after him, fearing he took human hostages...not knowing the humans are helping him.
Lastly, like Bumblebee in the 2007 movie, this is a temporary vehicle mode, when he finally meets up w/ Optimus & the crew he scans that Bugatti.
Just a theory, let me know what you think. I for one would love to see a little of the Drift story arc explored in the new movie!