Soldering is pretty straight forward. Though I don't have one myself, I've borrowed my friend's soldering pen on many occasions. You just have to be careful not to burn yourself or your bass. With a little practice, you can be decent at it in about an hour.
Tone and volume pots are different.
As for parts, check out Carvin.
http://www.carvin.com/products/group.php?CID=BEP
500k vol. pots: ($4.00)
500k tone pots: ($4.00)
.047 mf tone capacitor: ($1.00)
Output jack: ($3.00 or $5.99) depending on which style
Shielding/wire kit: ($9.99)
I've never heard someone complain about Carvin's electronics. I plan on swapping the electronics in my SX for Carvin.
Hope this helped.