OK, in an MT, this can be a little tricky, due to lack of space in the engine bay, but fret not!
Fitting an Intercooler has 2 main advantages:
1: Cools the engine/turbo, which means less chance of a detonation!
2: Cooler intake air = yet more power!
OK, what you will need to fit an Intercooler:
An Intercooler, best to go for a Renault 5 GT Turbo one, its smallish, and has the ends at the top,
these can be purchased second hand for as little as £40, take a look in your local ad's paper:
Left: Standard R5 GTT intercooler Right: Alloy replacement type
An old metro backbox/silencer
A metre of good quality rubber pipe, about 55mm internal diameter
A plenum chamber from a MG Maestro/Montego Turbo
The reason for the plenum chamber off a Monty Turbo is that its inlet points to the front of the engine bay.
Its a basic swap over for the metro one, take a look below at the pic.
The Intercooler can be mounted in front of the oil cooler, which means moving the oil cooler back a little, not a big
task, but if you look, it can be re-mounted about 2inches back from where it normally sits.
If you look at the picture below of a Intercooler fitted to a Metro Turbo, you can see where all the components fit.
1: The Monty Turbo plenum chamber
2: This is the rear part of the Metro silencer, recognize it now?
( Clean the crap from inside the exhaust pipe ok? ;) )
3: This can be either rubber pipe, or another exhaust piece
4: This is a L shaped piece to the turbo
5: Connection to the Intercooler bottom hole
Once all fitted, you can fit a proper dump valve to either the rubber pipe, or the metal one and fit an aftermarket dump valve.
With this Intercooler, temperature levels drop, boost drops a little, due to the fact of the increased space the Intercooler eats up between
the engine and the turbo, so you might need to readjust boost levels.
The diagram below shows an alternative method, instead of using a Montego Turbo plenum chamber...