• As the tagline says, the manga Wangan Midnight (Japanese version) is available to read in full for free on Young Magazine Web from June 2nd to 8th (you can check it out here).
• The entire dialogue is a callback to chapter 167 (or part 3 of Series 41 if we go by the digital release order):

A: Your coworkers probably all drive fancy cars like this.
B: That's not the case.
B: It's mostly just ordinary domestic sedans. Even among the imports, there are only 3 BMWs...
A: Hmm. Then how come you're driving this?
B: It's simple. I put everything towards this car.

To be fair, the "yo" that Seia adds to the end of her lines isn't really a verbal quirk in Japanese the way it is in English, but since Sensei questions her use of it, and it's also a Wangan Midnight reference, I went ahead and kept the "yo" in the translation.