thanks for the rapid reply .
i will first flash with one of the firmwares you discribed than i will put one of the 2 others on it .going to try it out tommorow since iam on my work right now .
one more (lol and last) question .flashing with odin means my stock firmware is gone.but what about my backupped firmware that i backupped with rom manager that stays on it ?
it should, though you could easily back it up to your pc which I would recommend anyway, to back it up simply copy the clockworkmod directory from your sdcard to your pc. and the samsung-firmware site has the XXJF3 firmware available so you could actually simply flash that through ODIN to get the stock firmware if you ever need to repair your phone. oh and remember that the roms require different firmwares, the samset rom requires the jm5 firmware and the modaco rom requires the jg5, so flashing jm5 and then the modaco rom won't work.