if anyone know after i put the single turbo like about 15 psi...should i changes any part of my engine???

At 15psi you're effectively doubling what the engine feels compared to naturally aspirated... Valve springs, bearings, rods, engine tune (retard timing and fuel enrichment), and higher octane fuel. Those are the basics that come to mind being non-specific to your project. Look around a 350z forum where you can see what others have done and their results.

first thing to go will be your clutch. I roasted my stock clutch and the JWT clutch too. Im running a stage 3 spec clutch now which I highly recommend. Your gonna also need a walbro intank fuel pump ,bigger injectors and a good piggyback like a turboxs utec.I would go no higher than 400whp, which with a single turbo should be easily attainable. I'm pushing 420 with the vortech supercharger and have problems putting that to the ground.

ya ur gonna have to upgrade ur clutch to a higher grade like stage 2 or depending on the turbo, get a light weight flywheel and most def a boost controller and turbo timer.

this is so close for saving up!!thanks for the comment guys cuz it help alots...im planning to get the act clutch this may so i will check on the stage 3 spec that u recommented,i also only boosting if at 10 to 12 psi when im going to the track if not then i just crusie with it arround 6 to 8 psi