if it takes more than 30 days to get the residence permit after arrival (s2) do you have plenty ?

You made a mistake between S1 and S2. S2 just allows you to stay less than 180 days in PRC. S1 allows you to stay more than 180 days. If you hold S1, you should apply for the resident permit after you arrive within 30 days. If you get a S2, it must state clearly how long you will be allowed (duration of stay) in PRC.