I would like to try adding reach on my Canyon Speedmax (rim brakes) and I can think of three ways I can go about doing that:
A) move pads and extensions as forward as I can (this is obviously the simplest solution but it still requires investing on some new accessories because of the way the mount and hydration interact with the bars. Also, it will eventually max out)
B) get the long stem version. This should add 2cm to the whole front end (base bar and extensions) but I think I will need to invest more in additional Canyon spares, including a completely new hydration and stem cover. It will give me more freedom of further moving pads and bars. As a side effect I will also be adding reach when on the base bar.
C) get new pads/extensions, potentially one of those many "super" extension kits that are claimed to have some very marginal aerodynamic impact because they bring bars closer to your arms. This is by far the most expensive option. Does it bring additional customisation? Is it worth it?

What are advantages and disadvantages of each option in terms of adjustability, handling, weight distribution, etc.? When are your head and arms too forward? Anything else I should be thinking about?