With 86,000 miles experience on my 05 RC....
Tires: I've had 6 sets, 5 of which were different. I'll continue with Yokohama Prada Spec's
Brakes: OEM's work outstanding however major dust, squeaks and severe wear to rotors will occur. I've done OEM rotors and EBC green pads, however, I'll stick with rotors and pads from Zeckhausen racing.
Oil Exchanger lines: If your truck still has them replace them....now!
Power Steering: Same quick connect fitting on the HP side of the steering pump as found on the Oil Exchanger lines. Seems to be less prone to failure however great time to replace this one fitting when you flush your PS system.
AC: Often passenger side will blow warmer than drivers. Have your AC person slightly over fill with R134.
Clutch: Many have had issues with slave/mstr. Imho its primarily those who abuse or have no idea on how to use a manual....
If you need to replace go with Viper parts. My original is still working fine...:rock: (knocking on wood)
Cosmetic: Keep your steering wheel clean and conditioned otherwise it will look like crap in short order. I treat mine every wash and so far looks good as new. Clearcoat on factory wheels is marginal at best. Keep them clean, waxed and they will be fine, otherwise moisture will work its way to the aluminum and looks like crap. Permastar is a great alternative....my Permastar treated rims have over 50K miles on them and look perfect. If you do a drop kit make sure your alignment guy has a clue. Most shops will only due toe in and not get camber/castor back to factory specs. Most trucks (04,05) need modifying to the upper adjustment slots. 06 front suspension is completely different. Upgrade the OEM shifter to B&M....nuff said.
Personal observations: 04-05 are very similar. 05 have enough factory updates that to me make it far more desirable. Biggest of which is anti knock sensor. 06 is a nice looking truck however the interior changes ruin an otherwise nice styling upgrades. As previously mentioned 06 has different front suspension and electrical is Canbus system. Those who would consider or have purchased the quad cab....I don't see the reasoning. This is a sport truck....diesel would be better application in QC platform. RC can be used as a truck....hauling and towing with no issues. Payload is on par with standard 1/2 ton and when towing just remember to use your clutch with a bit of common sense.