I've got an SAR-1 (1999) that works very well.  There is no binding and everything just seems to fit.  If I built a good romy kit on a home-bent flat, how would it compare to the SAR-1?  I know it would depend some on the tools available, but what are the chances that the kit build would be as smooth as the SAR-1?  How long will a flat last if it only has the ejector and hammer/trigger holes heat treated?  Is there any reasonable way to heat treat the entire receiver at home?  sorry for the newb. questions, but that's me when it comes to building an AK.  I've done ARs and FALs before, but AKs seem to be a different beast to build.  

depends on how good of a job you do with the flat...

ETA: if your not sure about the heat treating check out some 100% receivers.
and yes they can be just as good as your SAR