• Servo extension cables (The stock servo leads are just long enough to get inside)
• Battery connection adapters or new leads to solder on
• Epoxy since there wasn't enough that came with it.
• Power transformer for battery charger (You might not have to pay for that if you get a different charger)
• A five wire balance plug to a four wire plug.

Tools that I have used

• Hot wire foam cutter. I made mine out of chopsticks, a clothespin, 9V battery, a rubberband, and some florist wire. One of the ailerons stuck during movement against the body. 
• Digital Multimeter To check my solders on the connectors.
• Soldering iron and solder
• Pliers

Some elaboration:

My SkyFun came with a Deans connector (the unsoldered part) while my batteries came with a XT60 adapters. My biggest problem seems to be what plug to go with (I like soldering) a compulsive person would get a scale and weigh them. I am going to be lazy and bet on the XT60 gaining a majority so it's time to cut the plug off my SkyFun and get to soldering.

I ended up picking up a CellPro from FMA Direct since HK was out of stock for the US warehouse and I was impatient and I didn't want to spend another $20+ on just S&H. I did buy batteries from HK though since they had them in stock from the US warehouse. The charger however did not come with an AC adapter so I either have to charge from my cars battery or get a power transformer. The other caveat is that my charger is a four cell charger while I only have three cells. What this means is that I have a five wire plug that needs to go to a four wire. Luckily the manual describes the wiring schematic so you can buy your plugs and crimp your own adapter wires.