It's quite easy (on paper) for a CR170.
I've looked it up, as I have a gauge to install once the weather gets better.
1) jack the car up at the front
2) remove plate
3) remove the entire pipe from intercooler to EGR valve (few screws from below and loosen clip from the engine bay of flexible tube to EGR valve
4) drill hole in the flexible part of the hose assembly you took off, so in the part that connects to the EGR
5) put a tap in the hole (15 quid I think I paid)
6) make sure there is no drilling debris in the pipes.
7) connect boost pipe to tap
8) reconnect and hook up all the electrics and boost tube.