You can go to about 1.5-1.75" without getting new caster/camber plates. I would strongly suggest getting new shocks and struts (KYB, Bilstein, Tokico, etc.) with new springs though.
BTW, anyone with Ford C springs, what kind of drop did you guys get?
you should get cc plates if the drop is more tahn 1.4 inches and even wtih my 1.3 my tires were worse on the inside (not that they didnt stock... just worse now) cc plates are rather cheap for the life they give you in the tires ify ou are planning on slamming it definatly do the cc plates. 2.0 is probabyl as low as you are gonna get with just replacment springs from a decent company. you will have a horrible time driving ANYWHERE but it can be done.... 1.5 is the limit for drivability.