the hiss, puff of smoke and engine dieing are all due to the intercooler pipe coming off. it happened to me when i installed my intercooler. i think the engine dies because the same volume of air is no longer going to the engine and that stuffs up the mixtures. I dont think it would have done any damage as it would mean less air being forced into the engine and thus too much fuel just making it sort of foul? im not too sure but i checked all my connections and after that everything was fine. In regards to your boost, did you notice any change? I didnt on mine, maybe you have another leak somewhere.
cheers