I wouldnt go more than 450 myself before changing pistons, and not more than 500 before changing rods, but seriously...to make a lot more power than that you would need a huge turbo, I have wisecos and t2 rods in my 2.4 good for close to 600HP if I ever decided to break every part in my motor before achieving that...my eventual goal is 400, I just like overkill(and I got the wisecos so I could rev past 6500 RPM in safety, not to mention the SRT pistons dont come .020 over, or didnt when I got the wisecos..and I got a good deal on the T2 rods bushed for a 2.4, not to mention no one has ever reported breaking one that I'm aware of, and there have been turbo 2 guys pushing 550), if I had a stock SRT4 motor(I do have a stock SRT block sitting aroundI got for free I intend to rebuild, previous owner spun 2 rod bearings)...stock bottom end would be fine for me