Actually there are different kinds of boosts, which you can add in different ways.
use energy boost.
If you look on your mafia wars home page, there is a button to allow Mafia Wars to update your status, if you hit that, then it will show a link for people to add you
add them first as friends in your facebook account before adding them in Mafia Wars.
if you want to have more mafia members, join pimping services. they will boost your members in a day.
It is the regular people in your mafia that are very good or your friends that you put in your top mafia to boost all your stats.
Go to INVENTORY, then BOOST - a new feature! It's $2,000,000.
You can only add friends that play mafia wars, random people cant be added unless you add them on your facebook.click on the my mafia tab in mafia wars, (it is on the right side)Join a pimpin group like this one. http://www.facebook.com/groups/161828970620373/
once you attack or fight someone.
Add people who post on the Mafia Wars main page or other forums. It's easy to add someone as a friend, add them to your mafia, then delete them as a friend after. You can also post a request yourself so people will add you automatically.
Delete them as a friend and dont add them again
you can add mafia members over 501 but you can only take 500 to a fight.
You can't download the MySpace version Mafia Wars, you can only add the application on MySpace or Facebook.