Do the radiator hoses on an impreza turbo preassurise when running normally? I can depress the sides of the hoses a reasonable amount when the engine is at normal temprature but I'm not sure if that is normal. I've checked the thermostat and it appears to open and close as expected and the water temperature is the similar at the top and bottom hose.

 

Yep a sound system no leaks etc header cap on you'll pressurize the system. Hoses won't be rock hard though. Pretty much even temp what ever hose you feel. Although splitting hairs the top hoses my be a tad warmer than the lwr.