[1] Almost no chance the computer will get "fried." At most but very unlikely, you might fry a USB port or controller. USB ports are designed "hot swappable" meaning you can plug and unplug stuff whenever without killing your hardware, but it's still best to follow device instructions. The only Tuneboy link instructions you should follow is to plug the thing in with the bike ignition off first.
[2] That bike fuse won't affect Tuneboy interface with computer at all.
[3] Another unlikely thing. It's just another application that can be uninstalled like others. Wayne didn't program malware. At worst, Windows might lock up and you have to reboot.
[4] Sure can! If you aren't straight about how much the thing cost you (and her), plus all the extra "love" time the Tuneboy will give to you and your bike, well... The Mrs. might well not put up with it. She may be looking for a divorce attorney within a week. That's why I keep all my gifts to the Mistress hush and I only sneak out for a rendevous late at night when me wife is sound asleep. :lol: