Yes and No, it is illegal to live in the State of Georgia for longer than 30 days and fail to register any new or used vehicle in the State of Georgia that such person owns. Under OCGA 40-2-20(c) any person who fails to register said vehicle as required under the Code shall be guilty of a misdemenor. However, if the car is owned by the business the car should be registered where the business principal place of business is located, so to be on the safe side you may want to register the car in Georgia.
You need not obtain a Ga drivers license unless and until you become a resident of Ga. Generally, a resident is a person who intends to reside in Ga indefinitely. Therefore, a college student who lives in Florida and comes to Ga to attend college is NOT a resident of Ga and need not obtain a Ga license OR register his or her vehicle in Ga. Similarly, if a person from Fl comes to Ga for business and does not intend to remain, she needs no Ga license. If however she intends to stay in Ga indefinitely, then she must get a Ga license within 30 days. If the vehicle owner is still the Fl business, it need not be registered in Ga. However, as with many things in life, a strict observation of the law does not mean that you are immune from police detention. The police may stop you many times and it may be worthwhile to get a Ga tag and license to avoid the hassle.