So you exclusively buy pre-2000's shitboxes? Is there a reason for that, when you could literally just rip the modem out of a modern car instead?

If you're driving such old cars, I have to assume you're mechanically inclined. At which point, a simple bypass cable or literally just removing the telematics unit out of a modern vehicle should not be too much to ask for.

Bonus points for gaining moderate security with immobilizers that way, so any random guy can't just start your car with a set of wafer jigglers.

Why would you assume it’s a shitbox

My 2001 Tundra is a beast that will never die, has amazing AC/Heat radio etc…

There are fleets of garage specials out there with low miles and tons of spare parts or are easy to maintain with a Chilton guide

I started my working life fixing cars and obce they started putting in electronics it became impossible.

So I stick with things I can fix