cid:49 is the best, with cid:52 u won't be able to customize and unlock ur phone.
so get the newest w300i cid:49 erom, get xs++2.2 from XS++ V2.2 - SE-NSE Forums.
put ur erom in the main box of xs++ connect ur phone with service cable and press flash, after flashing ur erom u need 2 flash MAIN & FS and add a custpack