I'm working on a car that sat for many years. To get it running well, I had to replace the fuel sender and pump, fuel filter, and rail with injectors. (Plus remove all fuel, replace some of the coils, spark plug tubes, water pump, a radiator, heater core... still lots left to do.)
Removing the fuel rail does require some work. Here's a tech article from Pelican Parts:
https://www.pelicanparts.com/techarticles/Boxster_Tech/25-FUEL-Injectors/25-FUEL-Injectors.htm
There's some good info there, but it does not say anything about removing the intake and all of the pictures show the engine OUT OF THE CAR.
A simplified list of what I remember:
- Disconnect most of the engine wire harness.
- Remove air filter.
- Disconnect crank case vent at front left of engine.
- Remove left side intake.
- Remove Secondary Air Injection Blower.
Now you should have space to access and remove the rail, but it is still tight.
While you are there, it would be a good time to consider changing spark plugs, spark plug tubes, and inspecting your coils. I can upload a brief video discussing it, but I expect there are already some better ones on YouTube.