This debate comes up time and time again. Some people think cam and some think intercooler. There are very real comparisons you can base your decision on rather than anecdotal testimony from someone who bought one over the other. Overall a cam like the xp/nic or similar grind should make more power than just adding an intercooler. It'll also allow you to rev higher and have an overall faster car.
The great thing about the cam is that actual volumetric efficiency is changed. With an intercooler you're simply cooling the charge... now you have to jack the boost up which creates more drag on the blower, higher boost levels make the blower less efficient (adiabatic and volumetric) where as the cam does the opposite.
As far as I remember they're both around the same cost. While some people will tell you an intercooler is easier to install the truth is they're both fairly complicated and you'll need to know what you're doing either way.
IMO the first thing that should be addressed on a 3800 is it's inability to flow air. An intercooler doesn't address that at all.
