It can be very random with which cars demand security access and which do not, typically you will only need security access if you want to reprogram a control module with different software, program a key or do an "add/remove" for a module, although not all cars will demand security access, it seemed to be more common that Aero models would want it.
As for the usb/serial interface, it's been a long time since I had to make one work (10 years!) but I think it was those with an FTDI chipset that were most reliable, some of the cheaper ones back then would not work.