Will getting new fuel injectors and fuel rail give my better performance?

 

No.

Stock fuel rail is actually good up to a pretty high HP figure.

Fuel injectors are only needed if your engine is taking in enough air to mess up the A/F (air/fuel) ratio and your injectors can't keep up with the airflow to maintain a proper A/F ratio because the flow rate is too low. Taking in a substantially more amount of air can be acquired by having a monster engine build, a turbo, or a supercharger. The faster you can take in air and fuel (efficiently and with a good tune), the more power you will make. You increase the amount of air you can take in by doing other major modifications, and then you upgrade the injectors to a flow rate that matches your HP goal.

Since your engine is not pulling in air faster than the stock injectors can inject fuel to maintain a proper A/F ratio, you do not need to upgrade injector flow rate.