I had two major failures of suspension of disbelief (the sex-in-a-Porsche thing doesn't count because it didn't happen and the guy lies like always). (1) The magic healing stuff, maybe called liquid platinum and (2) the magic drugs that knock you out and when you wake up you are immediately alert, no hangover even if you would ordinarily have had one.
I wish these things existed, but they don't. Such a bummer! (Yeah, I know about a bunch of martial arts goo to help with bruises. It's not that great.)
I had an ongoing problem with the cartel: it just isn't that easy to dispose of bodies, and even if this crowd was mostly people undercover for various government run operations, I'm pretty sure unrelated law enforcement would tend to run across them pretty often. I just didn't really believe that they could get away with what they took for granted.
I also had a problem with why Bastien didn't kill Hakim sooner. He was supposed to, and that would have solved a lot of problems.
Other than that, it is a well-told story and suspenseful. Hopefully I will not suffer a further impulse to read books in this series.