There's no real advantage to a later frame. Strength became a non-issue with the K1, when they went to the one-piece, integral, engine cradle.
Next year, this one will be officially "antique"...25 years old... which gives you the option of historical registration and easier/cheaper insurance options. OTOH, you're bound to 1993 D.O.T. compliance standards...turn signals, dual mirrors, for road use.
You may want, or need, to perform a few mods, like a steering stop, in place of the lock flange, removal of those wire hoops for the evaporative emissions hose. The 12v seat latching/locking setup is quite different from the earlier style. Not sure how many 12v-configured seats are available these days, or the seat locking assemblies + keys. The extra flanges can be excised and a 6v seat latch installed, you'd need to weld M6 hex nuts to the wheel arch. The sidebadge incuses are smaller but, oddly enough, 12v sidebadges can be found.
I did notice that this frame is really clean, no rust anywhere and you don't see that very often. For the money, it's a lot of value. I'd like to know how this seller gets half-priced shipping from UPS. Seriously, enter your zip code & his, 14x16x20 & 50lbs for package dimensions & weight, and see the estimate you get for shipping an engine...with the standard $100 insurance. A frame is lighter, typically just shy of 30lbs, packaged weight, but quite a bit larger and better than $70 to ship via UPS. FedEx is a helluva lot less but, still nearly double what he's charging for s&h.
