bubble arch

Thanks everyone who has replied to any of my posts regarding my 97 classic wagon. ( cutting out on full throttle in 3/4th gear ,mooing sounds ,over filled with oil)

However can I clarify a couple of points .As I'm feeling slightly confused by these new fangled turbo things .as I seem to have 2 problems overlapping

1] The wastegate solanoid on 97 cars is 2 port and sticks due to oily crud . it can be cleaned out but a 3 port can replace it much more reliably. how can I replace it as a DIY job as I guess there is another pipe going somewhere else?
I have cleaned it outso I'd like to change it

2] The dump valve on 97 cars is renowned for failing and is the bit that produces the 'mooing' sound and can also be replaced with a later one .Is it the grey plastic fitting on top of the inlet manifold just infront of the intercooler with piping to the front of the intercooler.If it is will cleaning help it like with the solanoid,or am I buying a new one ?