No, unless the turbo housing is cracked, the coolant passage is sealed. If you're getting more air pressure in the coolant system when you boost it's probably the HG. Get the pH tested.
What's an Aero bar? N/m, it's on Wiki:
http://en.wikipedia.org/wiki/Aero_(chocolate)... See... I can look things up! So, which kind/flavor does the foam look like? If you've got foam in the coolant, it's contaminated. Clean water doesn't foam and anti-freeze additives are formulated to prevent foaming. You should check your oil, if there's anything that looks like chocolate pudding it's contaminated as well (look under the oil cap). If it is just discolored the coolant could be loaded with rust, but I've never known rust to cause foaming.
Even if the compression were still looking poor I'd recommend against using any form of magic block & gasket sealant.