I had a 2004 XR 400. It took a while to figure out how to start it with only one or 2 kicks.
It was geared way to high for the type of trail riding around here at least, so that was the first change I made to it.
It had way more torque than my current WR250, but the WR is faster and feels lighter on the trails.
The TW is still the king of the trail.
Would love to put a sand paddle on your 600 and take it to the dunes.