I just got my 04 HEMI and i was wondering what kind of mods i could do to add more hp i already have flowmaster and also a k&n filter but still want more lol just wondering what kinds of things i can do for more hp

Heads and cam will give you plenty more power. Comp sells cams for the hemi, multiple flavors from low end torque to high end power. Head port work will compliment the cam you choose also. Just make sure the cylinder head shop knows what cam specs you are going to run so they can work the head over accordingly.

read through the sticky at the top of this section...should find lots of good info in there for mods that you can do

Best you can do with a naturally aspirated Hemi, without doing head work would be:
CAI, Cat-Back, LT Headers, Tuner or better yet custom tune, e-fan, cam, springs, damper, retainers & push rods. Plus torque converter and gears to get that power to the rear wheels...
I've got all but the cam (and springs, etc. that really just go with the cam) and the TC. I've had to take a break with the mods as my funds just went to replace my daily driver. But I'll be back on track and finish in about6 months or so...