My twa cents:

I'm old enough to remember big American cars before any computerization whatsoever. Every thing was a thing unto itself. The starter did one thing; started the car. There was an oil bath air filter, it connected to nothing else. That big V8 engine sat alone in the middle of its compartment, there was room for me to climb in with it. You could jump up and down on the hood (bonnet) all morning and not even mar the finish.
BUT: When something broke, it didn't give you much warning. You had to catch it in the act of breaking. You had to time the engine with a flash pistol, you had to pull and gap the spark plugs, change the distributor and wires out at intervals, and our car got 15 miles per gallon rain or shine, uphill or downhill. The steering wheel was about a meter around because it was not power boosted.
Comes computers. They make it simpler for car companies because everything goes wired to the computer, and the poor damn programmer is the one who does all the work; decides what is a problem and what is not, what gets illuminated when you flip from parking lights to headlamps. And the modern computers are tied to transducers, these are the somewhat expensive devices to be found everywhere in the vehicle which convert the analog signals to digital which the computer can make sense of. They turn what's hot and cold, fast and slow, vaprous and dense, oxygenated and non, into something the computer will use to detect problems and adjust combustion. So you can get 32 miles per gallon (or 7.5litres/100km as the Euros among us might figure it) as I did in a Camry at 80 mph/120 kph.
So computers make life easier for the car companies the car repairers, and occasionally, the car owners. They make life more difficult for the programmer, who does get a job out of it, and occasionally, the car owner. They make life more interesting for the forensic technician, who will be able to figure out where the stolen car is, how fast the car was going during the accident, and, of course, we are not far from dispensing with the driver altogether, the job of the aforementioned transducers and computer going into absolute total fucking control. But we will have loads less accidents, and we should have lower insurance rates in future except that we won't.