You're right about this, and my dealer said he could do it within certain limits. He advised against it because it didn't allow the alternator to turn fast enough to charge the battery. I heard this argument 10 years ago, along with the idea that oil pressure was too low below a certain RPM, but I had my old Evo set to 850 rpms for nine years with no harmful effects. I would still like to get mine down to around 850, though.

 

According to the PC-III software my idle spends a lot of time in the vicinity of 960.

The concerns aren't solely alternator output; or oil volume to bearings, etc. The pistons are cooled by oil jet sprays from the wristpin (as I understand it). Certainly it would be advisable to maintain at least some of that flow as well.

 

Good point about the piston spray. Mine stays in the 950 vicinity, too.