Stock Pistons
 

What PSI can stock pistons use with upgraded rods. Is engine capability just on rods or rods and pistons?

Rods limit but tune limits all 300+whp is acheivable before oilpumps become and issue, and i would look at springs for the cams as well. ;)

rings die after 25o..suposedly.

I wouldn't sweat them unless you are making over 300 whp on a daily basis.

I rebuilt my engine with upgraded rods and stock pistons/rings. I plan to go 15psi eventually, but currently only run 10 as I have done all the tuning myself on the street based off of other peoples maps and I have been hesitant to go up more until I get other things on the car sorted out better.

How much boost can stock pistons handle? I really don't think anybody knows the answer for you definitely. The major cause of piston damage is almost always in the tune from what I know (knock creates huge bursts of torque, killing pistons and bearings), but at a certain point normal torque will break the ringlands and I don't know what that point is. I think you are pushing it at 250 hp on a 1.6 and 275 on a 1.8. So basically if you are looking to do a mild boosted miata at 200hp, a stock engine is fine, but a crazy 300+hp miata should have a completely built engine.

Yeah I don't see a point in building out an engine halfway. If your engine blows, either add a stock setup and go back to boosting 200ish, but if your going to build it..spend the extra 476, buy the pistons (comes with rings) and do it right. Your better off doing it now, then having to tear it apart later.