Does anyone know how durable the stock 94-97 pistons are? I have read that they are good for +300 whp. Marc @ M-Tuned.com has written that 350 whp would be ok.

So has anyone broken the stock pistons when using the forged rods at certain power level without detonation?

I'm planning on going the m-tuned rods and stock piston route with my EGT motor rebuild. I figure I tune fairly conservative and its more of a weekend warrior/street racer so its not getting beat on too badly anyways so hopefully they'll hold up OK.

1.8 dohc, 215 compression with 10@1 cast pistons, 15 psi .50 trim T3/T4.

Bent 3 stock rods, no detonation, pistons are intact, minor scuffs on the sidewalls as I kept driving them with the bent rods until it finally died.

Miata cast pistons hold very well under boost as long the mixture is there.

Although, now I am building one with SuperTech 9@1 with M-Tuned rods.