Should I upgrade my turbo?

[sre30s14]

So I gave my car to my engine builder/tuner guy. I was hoping to just get bumped up to 300 BHP. But when he opened the motor he noticed it has 2JZ-GTE pistons in it and I thought my car was stock. So he had to tear down the whole block to see if anything was done incorrectly. So I am getting new piston rings now.

But I got thinking about making 350 to the wheels. Seeing that the pistons are great and what not. My question is, is it worth it? Is a new turbo going to make the car more enjoyable? Or will I just put around and be that guy who never goes above 4K RPM? Because I'd be seeing a thousand dollars on top of all of that sorta work. Manifold and what not.

In my head I am thinking I've done the 3 inch exhaust, the F-Con, Skyline LSD, Skyline Brakes, my intercooler has a dent in it, new piston rings, 2JZ pistons are sitting there, a beefier clutch, 500 ccs so why not just go the extra mile.

But on the other hand am I just wondering if I am being greedy for no good reason. What does 350 WHP feel like against 275 WHP or 300 WHP? I am probably gonna be running E20 so I hope that gives me a little more.