I used to have an epi pro v t-bird.
The black box is the active preamp.
What is the other end of the red wire connected to?
Can you post any pics to show clearly what it looks like?
If you want some roundwoundish zing but with the feel of flats, you can't beat Ernie Ball Cobalt flats. I use these on my thunderbirds, and have just put a short scale set on my squier jag shortie.
All of my mustangs have d'addario chromes.
These d'addario versions are good. Fender & Ernie ball also have their own versions in various colours — I have all three types plus no-name ones & a few old Grolsch ones. The D'addarios seem slightly easier to get on & off than the others.
in red: https://amzn.to/3uQ2wRB
or black: https://amzn.to/4a2C9rT
Its a Squier Affinity with a fake decal and a shítload of aftermarket parts.
A photo of the back of the headstock showing the serial number is conspiculous by its absence.