I'd say leave it as stock as possible if it is an integral part of your job. When people mod a car, they generally drive it harder and put more stress on basically everything, making it less reliable. Auto transmissions on average sedans were not built to take a lot of abuse, and they are not cheap at all to replace. Also, once you get past minor bolt ons, there isn't a ton of stuff you can do to a Maxima without compromising reliability unless you spend waaay too much money for it to be worth it (which would probably include a manual swap at some point).

While it means you would have to put your modding itch on the back burner for a while, I would strongly advise saving up for a manual project car that won't put your job in jeopardy if it breaks.