Hi Ron,
Hello to you in the beautiful NL from Southern California!
That's so cool that you got a Vetta HD, and are getting it up to spec!
I've received a lot of compliments on my Vetta HD tones for the last 18 years, including this last summer.
It will sound awesome for you!
1. No, I did not have to re-flash the firmware. Everything has worked perfect since the battery change.
2. I never had any problems with static electricity replacing the battery in the Vetta HD and Vetta Combo.
I wore latex gloves while I worked on the Vettas.
Here's a tip for the Vetta HD: Run it without Cab Sims through your aftermarket cab.
I've run mine through a Marshall 1960A 4x12 the whole time, and it sounds HUGE.
Let us know how the battery change goes.
All the best,
Will