> There is no way to adjust timing anymore.
You do it via OBD-II and CAN via software now, not by a vaguely semi-accurate twisting of a distributor. It's a heck of a lot more complex than it used to be - multiple lookup tables to build but for many makes there are software suites online made my enthusiasts and even performance timing and fuel curve profiles you can download for various makes and models. The benefits are huge; timing isn't driven by RPM and vacuum any more, but by actual power requests made by the position of the throttle position sensor, and air intake is now metered rather than a moronic mechanically-driven butterfly valve that you'd find in a Quadrobog carburator, and the best part is modern ECUs are often learning ECUs, where they test the fuel to see how lean the mixture can run and how far timing can be advanced without pinging, maximizing BOTH performance and economy.
I'd rather give up having to constantly replace worn distributor caps and rotors and monkey around with a timing light for the increased overall efficiency and reliability. Yes, the coil pack-on-plug design is more expensive to service but when the coil packs normally last 200K+ miles, who the heck cares? That would have been about 10 distributor cap and rotor sets, plus many sets of ignition wires. Good riddance to distributors and quadrobog carburators.