If you are new to modding, you can fit 3mm led's in just about any spot that you can do a 0603 smd, and save a lot of frustration
basic necessities:
rosin soldering flux, expensive but will last forever,
thinnest solder you can find, .032 has worked perfect for me
15 watt soldering Iron and sponge
tweezers if you use 0603 smd,
scotch tape for 0603 smd's- super resistant to heat,
hot glue gun
super glue- only use to cover solder on 0603 smd's for a stronger bond
basic small Phillips set
2n2222 transistors and 100ohm 1/4 watt resistors for psp slim
Drill, and various small bits