Notice in this picture how the piece of piston that broke off apparently melted itself back to the top of the piston in 2 seperate spots!!

 

Here is the second shot of the melted material..

 

Here is the skirt of the piston.Notice the grooves cut into it.The block appears to be fine with the exception of one or two hairline scratches I am hoping a good honning will clean up and not have to overbore...I know you can not feel them to the touch but the scratches are visible..

 

And here is the piston next to the coorisponding head chamber.Notice the classic detonation marks..Im guessing the heads have to be re worked at this point..

 

Here is a close up of the heads..look like I need new valves and a good port and polish No?

 

are these pic from your motor?

 

No My buddies motor that Blew..I took the block from him..

 

Of all the 350Z pistons that I have seen with cracked and broken ringlands, that is the only one I have seen where the piece actually broke off in the combustion chamber.

 

If the OEM had not used a PM skirt coating the groves in your bore would have probably been significantly worse.

 

I dont know if this helps shed some light on the ability of the APS turbos or not but...

The APS TT kit uses two GT25/35R turbos, I dont know any other specs as these would contribute to the final flow abilities but one GT25/35 (non R version) on a RB25DET can put out ~370rwhp@around 17psi with various mods like cams etc, this is one example and im sure there are other lower and higher examples.