I installed the cap upgrades to my LS-9;s last fall, and it was well worth the effort. It is hard to believe that adding some small bypass caps can make much difference, but they do. You will like the results.
As I remember, my crossover board did have short standoffs. It had 5 screws, one at each corner and one in the center. If you forget about the that center screw, you will remeber it when the board will not come out after removing the the 4 corner screws. The only difficult part of the job was removing the Ersa cap . It had a lot of adhesive (hot glue) holding it to the board. I just got an exacto knife and slowly cut away a little at a time until I got the old cap loose so I could de-solder it. It probably took about 5 minutes or so to get it cut loose and removed. I also did the upgrade without removing the wires. Tthere was enough play in the wire lenght so that removing them was not necessary.
Have fun, and enjoy!
Mark