I ordered this kit from Robot Kingdom:
http://www.robotkingdom.com/mp05kitr.html
The kit is super cheap because it has rusty screws:
So I went to Home Depot and picked up some 6x5/8 and 4x1/2 screws to replace the rusty ones:
The 2 screws on the left were replaced by the 6x5/8 screws and all the other screws were replaced by the 4x1/2 screws. Even though all the screws are different lengths, you can replace them all with screws of the same length.
After removing the screws and cleaning things up with Q-Tips, there isn't a trace of rust anywhere on the plastic. I changed the philips style round head screws with robertson style flat head screws but I think it looks great.