There are tons of things you can do to an 04. On mine, I'm doing a little of both for power and looks. Here are some good websites:

pfyc.com, 3800performance.com, wbodystore.com, ZZperformance.com.

Here are the mods I've done to my car:

MSD Blaster Ignition Coil Packs, PRJ Performance Ignition Wires, K&N Air Intake Kit, Ram Air Tech Hi-Polished Billet Aluminum Engine Supports, Ram Air Tech Hi-Polished Billet Aluminum Side Supports, Caspers Electronics Valve Cover Breather Assembly, Street Scene Speed Grilles, Auto Ventshade Projektörz Headlight Covers.

I just ordered a performance PCM by Digital Horsepower and am currently buying parts for a new exhaust system that will sport a 3" downpipe with a high flow cat converter and Flowmaster Super 40 mufflers.

There are plenty of things you can do to these cars for both power and looks.

Here's my car: http://www.cardomain.com/ride/2917050/1