I've been looking around a bit online and it seems that 165 SR 15 or 165 HR 15 tires are getting quite hard to come by. The only one I found was a Hankook via the Discount Tire site. Any savvy shoppers out there who have bought original-size tires for their 914 recently and can point me to sources?
Most 914 people are less into originality than improving the (already-excellent) handling of the car. Therefore, the most popular tire sizes for 914s without modified fenders (or with "slightly modified" fenders, e.g. the fender lip folded flat) are 195/65-15 or 205/60-15. The 205s do not fit well on some 914s, due to the exact setup (particularly the amount of negative camber) of a given car and due also to individual car-to-car variations, so 195s are generally considered the "safe" bet.
As you seem to have noticed, it is difficult to find any decently-grippy tires in 165/80-15, the original size. (When no "aspect ratio" is listed, the assumed number is "about" 80.) For quite a while now, the only tires I ever saw in that size were the "super economy" type tires--read that: very cheap and not grippy at all!
For those who are into originality, it sounds like a very good thing that Coker is starting to reproduce the XZX in 165-15. You'll find that they are not spectacularly grippy tires, but they will look correct on the car.