I  just picked up a set of AGX's and was wondering what would be the best setting for overall ride and if I should get new strut mounts???
 
Keep it on the stock setting for a while to let them break in.
 
all of the above and you may as well replace the mounts while you in there.
 
 
if your mounts look bad, now would be a good time to replace them. 
as far as setting, like said its up to you.  break them in first then go out for a ride on a setting and if you dont like it, pull over, adjust and keep driving.  do this until you have something you like.
 
 
I would recommend new strut mounts.
Dan Trump

2004 Cavalier LS Sport - Victory Red