Just found this thread, so I will add my info:
Bought a 2000 orange/black/white SERG new in 2000. Had "stage 1", Air filter, SE exhaust, PCIII and dyno tune done by the dealer at the 1,000 mile service. I installed Heritage bars, Progressive shocks and Race Tech cartridges in the forks at around 15,000 miles, no other mods for the next 56,000 miles. At around 57,000, I checked the cam chain tensioners and found them 95% gone. Had my indie shop install S&S 510G gear drive cams.
At 84,000 miles, stator went out, replaced by dealer. At 130,000 miles in 2012 I started chasing electrical gremlins, found a few wires rubbed through or pinched, but the motor still ran great. Had a cross-country ride planned and was worried about breakdowns, then happened to see another O/R/B SERG on e-bay with only 14,000 original miles on it. The owner was a motor cop who rarely rode it, added some chrome but otherwise it was bone stock.
Bought it, changed the bars, added Progressive shocks and Monotubes, replaced the cam chain tensioners with the HD hydraulics and oil pump, basically set it up exactly like my "old"one.
I've put around 30,000 miles on the "new" one so far. I would have liked to keep the "old" one too, but having two bikes just wasn't in the budget. Added a Hannigan Sidecar and a trailer hitch couple years ago. That goes on for long trips, comes off when I want to ride on two wheels.