Primordial, I haven't tried cleaning my intercooler yet, but using alloy wheel cleaner sounds as though it shouldn't cause any harm. When it comes time I think it'll either be using alloy wheel cleaner or degreaser and make sure it's rinsed off well.
Just have to be really careful with the fins, just like the radiator core. The only downside I can see with the liquid/spray cleaners is how to get any solids, such as bugs and dirt, out without damaging the core?
What about the inside of the intercooler? Are you going to clean the inside as well? What are others opinions/advice on doing this?