Sideboard options:

Bogle : Runed Halo, Spellskite

Burn : Mark of Asylum, Spellskite

Sideboard:

The 5 affinity SB cards are really self-explanatory.

The other 10 cards are there to tackle problems, that are difficult to handle with just the main deck:

Against UWR (which is a rough MU) i just try to make it as hard as possible for them to destroy my creatures. In my experience the easiest way to win is to just negate all their removal with flicker effects and damage prevention effects like Burrenton Forge-Tender and Mark of Asylum. Combined with the Maindeck Mana-Denial plan and the help of Choke, that's your best shot at winning against UWR.

It's a lot less complicated against the Twin decks. If you have a Turn 1 Vial, your Win Percentage is about 80%. If not, it's probably around 20%. Without a vial it's just very hard to start applying pressure while keeping mana open to represent tricks and removal spells.
While building the SB I actually didn't focus on beating Pod at all.

Against Pod decks i only bring in the 2 extra removal spells, the 4th Aven Mindcensor and Akroma, Angel of Fury. Basically I'm just trying to execute my MD-plan more efficiently.