are thay any good,or a waste of time and money???

For unblown cars they are excellent giving very similar heat expansion characteristics to normal cast pistons with similar strength as forged units. This means you can run much tighter bore gaps than forged and hence make more power than forged pistons and withstand higher revs and compression than cast pistons.

However for > 1 bar on blown motors I would stick to forged pistons.

Hyper eutectic aluminum -silicon alloys have really good bearing characteristics ----