1. Basically there is no difference..just unique server items and stuff like that..and as u said..quests etc.
2. capital mistakes: the server was under attack lately..dont make the mistake to take following items from other players who might be hackers (Parasetic gene flow, Sonic team armor, proof of sonic team, black psycho crystal) but theres an other topic for that i think. just zap through the forums.
3. there were some germans among us who arent that active anymore or at all, but there are some. but mostly from uk,usa,mexico,spain,brazil (please dont judge me..just what im aware of )..i dont think there is a german team..that team would be small and not very effective, as in helping each other..more player..more help..BUT..u can make your own team.
4.Skinning PSO is no hacking. it has nothing to do with the server actually. modding the skins is all bizz of your computer.
Welcome and have fun
P.S.: ich habs auf englisch geschrieben damits auch jeder versteht