what forged pistons brand

[filh]

As expected , I broke my 6th 4age engine . Always same problem : rings and ringland broken .
It's a rally car and it's a heavy use .
Engine only have 2 small CatCams , and a lighted flywheel.
Always fitted stock pistons ([u:4b59bf6630]oversized 81.5mm bore, 18mm pins[/u:4b59bf6630]), but unavailable now from Toyota.
Mostly use Mahle .
The engine was tuned on a Dyno bench : fuel management and timing were correctly fitted.
Problem seems to come from a too high C.R. due to multiple head surfacing.

I think the best solution could be to fit stronger forged pistons .
But most I found (Wiseco, TODA) are dome top . Impossible for me to use as CR would raise a lot more .
I'm searching for flat top forged pistons, but don't know which manufacturer or supplier could help me .
Any experience with this ?
Saw Arias , but don't know if they can fit my engine .
http://www.ariaspistons.com/products/toyota.html

Phil