Hi Tom, thanks for the welcome. My '03 is pretty darn clean with just over 110K. I'm assuming the front end ha been leveled since I have 285/70/17's on it that only rub a tiny bit. It has a Spectre intake that I just put an AEM dry filter on. Found a hole in the Spectre filter... hope that not too much dirt etc. made it into the engine.
I have the leak at the tailgate/tonneau transition and adjusted the gate as tight as it will go today...hopefully will reduce the leak somewhat.
I'm a DIY guy so will be swapping all fluids for amsoil over the next few months as cash allows.
Sounds a lot like my rig. I have 113K miles, Spectre intake, and the leak as well. 17" rims were standard on my year. I put the larger slotted and dimpled brake rotors and calipers which only fit if you have at least 17" rims. Way better braking. A new filter will run you $50 at Autozone. They had to order it, just took a day or 2. I bought a 2nd so I can just switch on the fly and take my time cleaning, drying and oiling the dirty filter.
Cheap? Kinda depends on what money level one considers cheap. A nice mod that you may consider cheap is to replace the standard headlamp bulbs with 60 watt LED kit. Amazon has them and Ebay as well. Just make sure it the no EMI model. My first set killed the radio with noise when they were on, so I had to upgrade them. Sure makes it easy to see the lines on the road when raining at night.
So an update.... after adjusting the tailgate as close as it will go, it started to drop while driving on the interstate. So adjusted the strikes back out a little and seems tighter now. I think I'm going to have to wait until spring and silicone the gaskets on the bed panels and hopefully seal the leaks and live with the gap at the gate.