Thing is, it might depend on the intercooler too. If you are using a high quality one ($300+ easily) then you may not see any issues. Most of us are running $100 eBay ones....
On another note look at this thread:
http://www.bimmerfest.com/forums/showthread.php?t=120057
In my setup, I have two analog pressure sensors, one mounted before and the other after the intercooler. Both send signals to a A/D convertor and into a micro-processor. While a pressure gauge can give a more continous needle reading, a A/D converter captures data at a preset sampling rate. This means I have analyze pressure gradients rather than instantaneous pressure points.
Here's a sample of a data I gathered from one track session at Buttonwillow. Graph shows Pre-IC and Post-IC pressure data. Please note: 0.1kgf/cm^2 is about 1.42psia.