Perhaps I best offer an explanation to the above.
There are 4 things I have done we mention in abbreviations, these are.
1. The connection between snorkel and the box with air filter in it (Airbox). Any of the 4wd shops will happily show you a photo of a car driving through deep water, take lots of your money and fit a snorkel for you. Trouble is, the way it connects to the to the air box is not always water prof which means in a deep crossing you will draw water into the airbox, it is just a matter of how much as small amounts can be tolerated. The small amounts will soak into the filter material and eventually with more driving engine heat will cause it to evaporate.
I have made my connection water proof all the way to the air box as I hope to play in deep crossings.
2. A result of the above modification is the connection from snorkel to air box is a larger size and with less restrictions which helps the turbo come to life earlier in the rev range under a given load, which = better low speed performance. In some cars there is a knock on effect for this of noise from the air intake system being heard from the snorkel, but for my 100 series it made no difference, the 105 it was a loud sound of the air being drawn in. A louder volume setting on the stereo fixed that.
3. I have swapped out the aftercooler for a bigger unit, the after cooler (Not intercooler as the advertising people prefer to call it) is for cooling the air the turbo heats up from the compression of the air and the heat transfer from the exhaust which drives the turbo. The cooler the air is when entering the engine the more dense it is and the more performance gained. Also the engine combustion temps are lower due to it. The unit I have fitted is possibly the biggest which would fit the space, it will reduce the compressed air temps a lot more then the original unit.
BUT, there is a knock on effect with the install of it and that some of the forced air flow to the A/C condenser and engine radiator is reduced, in the case of my 100 series, this effect is minimal.
4. I fitted a small air volume tank for my 12 volt compressor to charge up, the idea being as I'm driving of the beach I turn it on and the compressor charges up the tank to around 10 bar, so a 4 litre tank at 10 bar is = to 40 litre volume of gas. Road pressure for tyres is 40 psi (2.7 bar) so that pressure converted to volume means that I have about 28 litre volume of usable compressed air in the tank ready to go as a surge to fill the tyre more quickly, the compressor still runs charging the volume tank when I walk from 1 tyre to the other.
Hopefully that helps a bit.....