I imagine s/he was referencing the fact that most modern cars have on-board computers, that are eminently easier to crack (and much less detectable) than through mechanical additions / tweaks.[1]

H.N. trawling the CIA's old files? How I miss thememoryhole.org. 2009, RIP.

For the record - I'm not going to comment on ancient cold war documents that could be Blue Sky Think-Tank work (and certainly don't look like professional training manuals). You'll probably want School of the Americas manuals for that[2](ahem).

[1]For example: Carshark http://jalopnik.com/5539181/carshark-software-lets-you-hack-... [2]https://en.wikipedia.org/wiki/School_of_the_Americas_Watch