I do understand that the GPS library is very useful but in my case
the custom function that i now use is the receive with start and end markers suggested by Robin2 in this topic Serial Input Basics - updated. In my case it also is time critical. meaning that it keeps track off different events and the time that they took place in ways that affect the flow of the program. Messing with it will require that i have to change not only the code but the whole philosophy behind it.
Thats why i do not really want to do this. At least not yet.