Hi. Solid advice from Tuff. Even though this is a higher end saber... I'd stick with finding one sound font that you find best connects with this saber and your use for it.
The v4 is really nice to have those extra sound and mute options... but ultimately most owners rarely switch out fonts once they find the one that resonates with the saber. The Obsidian sound standard font is quite popular with a lot of owners.
If you still want to switch it out... factor in the charge for removing the v3 board, cost of v4 and shipping fee both ways.
You can email them with your questions below. Provide specific details regarding what you want and US will let you know if they can do this and the total cost.
info@ultrasabers.com Expect a minimum of a few days to receive any reply.