I run a jammin buggy and i found the best droop screws are the associated ones. they are like the 4mm button head screws in shape but they are machined for wrenches on both ends, put the button head towards the chassis, the decrease in chassis wear is very much worth the price.
here is a link to them
http://www.amainhobbies.com/product_...T-Droop-Screws