Chrismaynn

Hi all, I know this has been covered extensively but after a bit of reading i couldnt come to a conclusion so I was hoping someone could answer this quickly.
Ive recently purchased an '08 is250 rwd and am looking to lower it with megan ez coilovers (hope theyre a decent choice) and put some 19s on. What is the max. width i can go front and rear, im happy to roll and pull the guards and get some camber going to have a nice flush fitment. Also help with offsets would be appreciated thanks guys.