GSP or no, most parcels from the US arrive in 15 or 20 days from shipping.
There might be a slight delay due to the heavy holiday mails, heavier every year as more and more people shop online, forgetting that online buying is mail order.
There is no public tracking from the GPS. Occasionally a little info is available, like the container that your parcel and thousands of others has crossed the border.
There is no border delay because duty and tax have already been assessed and collected.