Lets talk about the first build:

You build Torrment first,since you can be behind but still help your team and yourself.

You're next item is the hurricane. This is good item all around and helps with farm and pushing.

Teemo with attack speed is just evil. . so Greaves.

Having a rylai's on top of your slow from your shrooms and the burn from torrment its an easy way to get kills or when you team dight by tossing your shrooms in to help win.

Hexgun is a great way to get health back and stay in a team fight. with your attack speed you should be okay as long you place shroom to help.

Deeath cap is the iceing on the cake. You get so much extra ap as this is your last item. Kill people never seemed so easy.

For this build is if you are having a tough time and need more shrooms to help out your team and control the battle field.

Get yourself a MCon. You get a sweet 100 ap 20%cooldown and everytime you level you get some kills or help get em. you get mana back.

Lich Bane because if Sona can kill people with it. Why cant you?

Abyssal for the sweet sweet Mr and extra magic damage.