[das2123]

First of all, welcome to the forums, glad to have ya.

Since you have an R/T, you have the 150 HP magnum engine in it, which is a nice place to start. You need to ask yourself first if you want to keep the motor N/A or if you wanna turbo down the line. Then you can come up with a plan for the engine.

Most people do the following mods to the engine first:

1. Cold Air Intake or CAI (AEM is a good one)
2. Underdrive Pulley or UDP (Modern Performance sells a nice one)
3. Header (Pacesetter makes a nice one for the SOHC engine)

I'd start with these if planning to keep the motor N/A.

If you wanna turbo the car, then I'd look into rebuilding the engine first with stronger pistons, rods and whatnot.

A very doable engine swap is the SRT-4 engine.