Take ownership dude, you typed it, it's yours
I've eyeballed Gulfstars, Pearsons, Endeavors, and of course Irwins in my whirlwind tour of mid 80's cruisers before settling on my Irwin as the apex of the price/boat curve (that week, of the samples I saw).
In my un-informed, un-trained, but well read and very observant mind all of this 'class' of boats they generally are built to the same scantlings, thickness of hull, backing plates - all that stuff.
Year of build matters because all of the yards ran into money troubles and tried to cut corners at one point or another. None of them shut down production at the height of quality.
My major difference:
The gulfstar and the pearsons both used particle board for the furniture - and open edged particle board at that.
At the boat show last week I saw IP's with deck pulls in the sole - open edged plywood (not trimmed with teak). Granted you can't see it until you pull the access up.
My Irwin has even those edges trimmed in.
If you go there, where else is it fugly?