I'm not big into mods, but I also added the K&N and the HPD and I think it was money well spent. Between the look and the sound of the HPD exhaust, I'm sure most people would agree that it is worth the cost. It's hard to tell how much of a performance boost it provided, but it sure feels and sounds stronger and faster, so that alone was worth it to me. It makes a fun car even more fun to drive, especially in sport mode. Enjoy!