I did the revalve of the XR4's forks yesterday, threw in some .43kg eibach springs and new seals while I was in there. Pretty easy mod, it took about an hour on the first leg and about 30min on the second. I was able to do it w/o any special tools. I did need to use a airwrench to remove the compression stack out of the bottom since I didn't have the special tool to hold the dampening rod, I also made a seal driver out of 1.25" PVC coupler. Cost: about $135 including oil, sure beats the $300~400 that a suspension tuner would charge.
I haven't ridden it yet but they feel good, thanks trailryder42!
the procedure if anyone is interested.