I apologize for not being more specific. I am NOT saying that they are bad boats. We loved ours, but I have always been of the opinion that their overall construction was below that of a Pearson, Tartan or C&C or Sabre. Again, this is just a very general observation. I believe that the original price for Irwins were at the lower end of the scale. This was not because Irwin was a brilliant business man.
Things to look for: leaks at hull/deck, stantions, and chain plates. Original ports were cheap (but most have probably been replaced), deteriation of rudder post, steering assembly was undersized on ours, original running
rigging undersized. Method of fastening interior joinery was marginal. A good surveyor will be aware of other items.
There are just as many positive things to be said about Irwins. Have you checked under Sail-nets "Boat Check".