How much to cut cups?

[smashingchuck]

I think there is a lack of info because most guys that are serious about getting low ditch the cups / factory control arms in favor of tubular control arms.

At any rate, this is what I would do: Install everything and measure. If the control arms don't hit the ground measure from the ground to the control arms... and I would start by chopping half that distance off the cups. Personally, I would not lay the control arms directly on the ground. The part of them that hits first is very "tender" and is easily mangled by the pavement. I don't know how many times I've accidentaly scraped the pavement (with my control arms) trying to get that "fairground cruising stance" just to figure out exactly where I was at. I have now set my truck up so the control arms are about 1/4" off the ground when layed out, so even if I get a stuck valve or get switch happy, I'm not throwing gravel onto my chassis, and tearing up my expensive control arms.