Yes no alternator change required. And please stay away from the capacitor too. It puts additional load on the charging system as ur alternator then has to charge the capacitor besides the battery. What i have learned is capacitor is not meant to solve/improve ur charging system infact it put additional load on it.
Its meant when ur charging system is enough to support the system plus a capacitor and u do not want the voltage drops tht occur for a fraction of second on some frequencies no matter how good ur charging system is. The capacitor here will store and provide tht charge to help tht fraction of a second situation to stabilize the volt and play those frequencies at a stable voltage.
This is the reason most builds focus more on an alternator/battery and least on a capacitor. But since we do not have the variety of alternators and good hands to do it, better stay away.
A bigger battery could be helpful if u dont listen to the music at the max volume all the time u drive and let the battery charge too. U could easily get around 1500rs for ur battery and pay the difference and get a bigger battery but if i were u, i would first see if mine has trouble to deal with.
If im wrong, i would like to be corrected.