This was an attempt to appease the then crying foul N/A market with parts, parts they never bought or intended to buy to they pulled the plugs and sold the few sets at a loss simply to clear the stock. IF you can find a set of their heads for a build they are great!
You can still get the springs, retainers etc and use them on your heads. Ive inpsected a set of their heads well built and they port and polish them good quality. If you aren't planning boost save your money :0