Violence in games are dangerous only for those that cannot make the difference between the game and the reality... Unfortunately, maturity is not a question of age... Some people are 50 years old and can't even still make the difference
For changing the forum width, just edit the overall_header.tpl file and look in the beginning for the first <table ... width="..." ... > code. Normally it's only width parameter you will see. You can change it into xxx pixels (only number) or into % (xx%)
You can export the phpbb_users table (if your prefix table is phpbb_) and just import that file into excel or access... i'm not sure because i never done this, but if it's organized with tabulations, i'm quite certain it worth a try.