Shielding and Wraps
Because of the position of the turbo, it is very important to shield components of the engine bay from the intense heat. Your master cylinder reservoir as well as brake & water lines sit right next to the downpipe. There have been number of cases where the reservoir has melted and resulted in brake failure.
A number of turbine blankets and shields are available for all types of turbos. Not only do these block most of the heat from radiating out into your intake, brake lines, coolant, etc., they help keep the heat focused over the turbine an tranny tunnel and may increase the turbine’s efficiency.
And since a lot of the important lines run near the turbo and manifold as well it is important to keep them protected against the heat as well. It is wise to wrap you water lines (two off the firewall), oil feed, oil return, brake lines, lower radiator hose (off the block) and dipstick pipe in heat wrap.
Heat wrap can be purchased from numerous vendors in different temperature ratings, shapes and sizes. As well as different mounting solutions, i.e, adhesive backed, wire wrapped, riveted, etc. A roll of 1.5”x15’ 2000° adhesive backed heat wrap can be purchased for under $20. This is enough to wrap all your vital lines with room to spare.
Wrapping the downpipe to reduce underhood heat will somewhat prove useless. 80% of the downpipe is under the car, not under the hood. It is in this area, that the heat leaves the engine bay through the transmission tunnel.
Not only this, but the material of the downpipe will deteriorate very rapidly if insulated. Your pipe will actually "flake" away and break into pieces over time.
Vents, Scoops, Extractors
It is always useful to get more ambient airflow to your intake. Devices like NACA ducts, TSIs (Turn Signal Intakes) and scoops & louvers allow direct airflow into the engine bay to scavenge.
Extractor hoods & louvers can also be used as a way to help the hot air escape better by directing the hot air off the radiator fans out of the bay via the hood. While standing/idling, the extractor proves a great places for air hot to escape. Not only will this decrease the overall engine bay temperature, but it should prove to increase the cooling systems efficiency by lowering the pressure behind radiator and allowing for better airflow through it.
Credit to M2CupCar on Miataturbo.net