Use the PBT CFW !
That will get them installed, yes. If they don't have valid signatures, they won't RUN, however (at least that's my understanding). It should be safe to install so called "legit" .cia's this way though, or system .cia's (though I'd have a hardmod before even thinking of doing this, because although the install process itself is safe, installing system .cia's is still pretty iffy business at best, and can very easily lead to system bricking).
