No dead easy

Mine was under the rear end near the fuel tank, I think s2s have them in the engine bay so are even easier... just don't do it with a hot engine and probably best to disconnect the fuel pump and run the car a while (won't run long) to drain the system pressure first.

It's worth a go as they are not that expensive and very rarely get changed unless they fail.

It is about the size of a coke can with two threaded unions on the "top".

Did mine and it starts first touch now, hot or cold.

Hope that helps
Ant