About 2 inches
No, but it will accept any kit of your choice meant for the stock piece.
Complete front end for what you want to run, plus tapered roller bearings meant for an xr100
On a 100 with a 19-inch front wheel, no. other setups it is possible in order for it to sit level.
Yes, it reduces the spring rate by about 20%
Yes, but we advise against it.