This is very much a "don't do this" response, but it is my experience. YMMV.
I bought a set of full-tread Victoracers for my MK. 1 MR2. I live pretty much in the middle of nowhere, sports car event-wise, so I only get to run maybe 4 - 6 autocrosses a year - and for the last 4 years, some track days at the relatively nearby Kart track, where each lap is about a mile, mostly second-gear with some third gear. To date I have more than 150 autocross runs on them, along with about 125 track miles. I am always very careful to store them in black plastic bags in a well ventilated garage that maintains temperature between 70 degrees in the summer and 45 in the winter. They are now 9 years old, with no visible sidewall or tread deterioration anywhere. With a good traction treatment, they are still about 1.5 seconds a lap quicker than the RE-11s I'm using now (the RE-11s allow me to run without changing tires at the track).
I know that this is an extreme case, and that old tires are generally bad, and these are pretty well done for, but my point is that these will get you a lot of laps and will last a long time, and will still work well - just buy a gallon of Formula V (or whatever you prefer) when they get kind of crusty and enjoy.
And yes, I asked Tire Rack about the directional indications, and they confirmed that Kumho changed construction shortly after releasing the tire so that they were no longer directional, but they never changed the moulds to change the sidewall markings. So run 'em whichever way you want.