guys i'd like to get my SR20DET tuned from a shop. what things will i need?

[91nissantwo40sx]

Ok i dont know but my SR20DET doesnt seem like its running like it should be. When i hit around 3-4k RPM the engine sounds like its on 7-8k RPM. The engine is just loud at around 3-4k RPM and any more than that it feels that my engine is going to blow up. I am not a mechanic so i really dont know if this is normal or not. From what i have read, you can set the rev limiter? maybe perhaps that could be my problem, i dont know.

Do you guys understand what i mean or should i try and explain it better?

I was thinking my car might just not be tuned properly, if so then what will i need in able for a shop to tune it properly?

Thanks