smelly, the PSD4 are excellent candidates for aging, I don't know about 18 years, I am one who thinks that there is a curve to it, after a while the benefits become less and less noticible. Again, I've never had an 18 year old smoke, ever, so if there are some of you who have a few, I'll taste them and let ya'll know.....LOL
PSD4 will mellow out, and the OOMPH that once was there will be much more mellow, but the flavor profile they develop and the complexity far outweights the OOMPH factor, I was floored when I tasted an aged PSD4, needless to say I am now currently burrid my last one for a long aging process.
E, I also did the same thing, I purchased some SIGLO VI made in Oct 03 (my sons BDAY) and will not open the box for at least 6 years, was hoping to haVE MY FIRST ONCE MY SON TURNS 10 AND EVERY YEAR AFTER THAT HAVE ANOTHER.......