what forged pistons brand

[filh]

I'm not expert in pistons . I'm a serial 4age killer
But I think the stock Toyota pistons were stronger , but it looks like they are out of stock now .
I used to compete with the same old stock engine for 5 years , whitout breaking something.

Speaking about broken ringlands , I don't know if the weakness is on the hole shape :
Each time I broke ringlands , it was between 1st and 2nd rings.

My machinist think about high revs in charge and for a long time .
Such as 1km flat out , big braking , and restarting for 1km flat out.
There is no sign of detonations on piston top , and bearings are in good conditions