I was looking for a theoretical base for tuning my boost curve, and found some usefull documents on the Garrett website. Since I did not feel like typing all the numbers in my calculator all the time, I made an excel file that helps a bit. Nothing fancy, but it works   If/when I ever find out how I can graph these numbers into an overlaying line graph onto the compressormap, I'll update this, but in the mean time just plot the data manually onto your compressor map of choice  
(If you like to work with imperial system, feel free to adapt. I added some conversions for metric)

Example of how I plot the data in paint 

I've clicked the button once, but I dont recall that it made any sense to me at the time. Does it consider VE and BSFC? For me it is important to choose different settings because I tune on various fuels...

Well, VE does actually influence the amount of air that will flow vs a given PR. (But I understand in EcuXplot this is integrated because it plots from actual data)
About the pressure drop, yes that is the missing piece (as is VE actually)I have accounted for it in the calculations, but I have not measured my actual setup. I was actually discussing this with a friend today, about the possibility the pressure drop acts as a percentage either than an offset when airflow increases. My guess is that on the intake side, the vacuum between filter and turbo will increase when the turbo is sucking in more air than the filter will flow.. Anyone measured this? Or just measure vacuum at maximum flow and use it as a worst case scenario..
I did read about one user here that installed a compressor outlet pressure gauge, I could tap into the compressor housing and record my gauge, this will give a real world comparison of my personal setup :-)
(Come to think of it, I will actually do this before I change my intercoolers)

Excellent imperical info, this is a great way to test fow ability between intakes. It does make a performance difference, because every psi you have to overcome in the intake, you have to add to the compressor to net the same MAP. It could make the difference between surge and no surge.

How is that possible? IC drop is on the order of 4-8 psi ... seems to me that has a much larger effect on PR (assuming PR<3) than 1 psi of intake drop.

I wasn't clear, I am referring to the general affect that pre turbo losses have on PR versus how post turbo losses affect PR.  I'd expect post turbo losses to be larger as you say, but for an equivalent drop in pressure those on the pre turbo side will have more affect on the PR than the same loss post turbo.

Ah yea I reread your post. Agreed 100%

In reality though, post turbo drop goes up much faster than pre turbo drop, such that it DOES impact PR more.