The dealer will try to sell you their stuff. That's how they stay in business. Your setup is fine if YOU are having fun. It's not always about having what atvmagizene says puts out the most peak HP. If your bog is gone from the dealer, then great! If you don't want to drop another 2k into a new 8k machine, your setup is excellent. I would keep your current motor setup and focus on things that make the quad better for you in the long run. Stabilizer, steering stem (if you're taller) and nerfs.
If you want to keep your current pipe and power commander and filter, the only other cheap mod to do is the 08 intake cam. You can go 08 yz450f (dirtbike) or 08 yfz450 (quad) the dirtbike cam has more low-mid, the quad cam has more mid-top. Either way, its an improvement. If you ride trails, go dirtbike, if you ride dunes, go quad.
The only gytr things I personally would buy are the kill switch (because it is plug in, no splicing wires) and the frame skid plate.
If you are on the quest for most HP while being reliable... you want: Vortex, FCI intake, and a full exhaust. For exhaust you want yoshi if you are riding in a sound sensitive area, or dasa shorty if you are in a non-sound sensitive area.
Good luck, and don't get caught up splitting hairs over what to do to the quad, its a great machine and you'll have fun no matter what you do to it!
Ride it like your health insurance deductible has been met!