I know cold air is more dense and will make more power but.... The heat shield will only reduce the temp the air enters the air filter by say 10 - 20'C... That's not going to make a difference as once it gets to the turbo its going to get heated to ~800'C.
Only real way to find out is to log AIT's before and after.
Best way to lower AIT's is a better intercooler (therefore lowering the density of the incoming air INTO the engine).
That's on the hot side (ie your air filter and before the intercooler).
Sorry dude, but thats totally wrong.
You TURBO may get to 800'C (or more) on the exhaust side, but the inducted air going through it is moving so fast, that heat dosent have time to transfer to it.
The actual act of compressing the air by the compressor side of the turbo is what in raising the inlet temps.
A modded turbo car will normally be running anywhere from 60'C - 120'C after the turbo. A decent intercooler can then knock it down to a more reasonable 20-50'C before it enters the engine.
I think your getting confused with the exhaust side of the turbo mate.
At 800'C your alloy intercooler would probably melt!