First of all, I finally got around to installing my SR5 gauge cluster- thanks to Stock87 for the webpage writeup, everything went in without any unexpected problems.

Also, I just put on new 30x9.5 Kumho ATs. My truck sees mostly highway driving, all at around 6500' elevation, with many slightly higher elevation mountain passes on a regular basis. With the 4.10s and the new tires (old tires were 235/75) I notice a loss of power, but not too bad. I wouldn't really even worry about it, except that my rear end sounds like it is in need of replacement anyway. At speeds of 65 and over, it hums louder than the engine noise. I have changed the oil recently, and oddly, there were no metal bits in there whatsoever. So, to add to the 18 billion posts on what to do regarding gearing, I'm looking for recommendations: should I just find someone selling a used 4.10 third (they regularly show up on pirate or elsewhere for $30-50), and swap that in, or would it be worth it to go to one of the local yards and find a pair of 4.56 diffs? I don't ever plan to go bigger than 31" tires, and chances are I'll stay with 30", so I don't think I need 4.88 gears. But, I don't know if it's worth the extra $400 or so that it will probably cost me to get the 4.56 diffs.

Any advice?