You don't have to have them, but its a good idea, esp with those expensive 18" tires man, you can get a much better front end alignment meaning your tires will last longer therefore they will pay for themselves that way and your car will handle better, you can also get more caster which will make your car more stable at higher speeds.
CASTER IS front to back, like the way a fork on a bike leans. Camber is side to side, that is what will make one side of your tire wear more, like what happened to mine before I had them rotated. The caster on our cars isn't adjustable from the factory at all. its preset at about 3* positive.
With C/C plates you can increase this to like 4, 5, or 6* positive and you have a more stable ride at high speeds.
that depends on what you want man, there is stock, and then there is better than stock, you should know that. Stock Caster for instance sucks 4, 5 or 6* positive caster is much better than 3* positive for high speed stability I mean even at legal highway speeds of like 65 or 70 mph. Also your people that do stuff like this Autocross sometimes like to temporarily add extra positive camber for handling, Caster/camber plates allow for this as well.
yeah, i know there is better than stock, but if he cant even get to stock cause hes too far negative, then he cant go positive.
the thing about going too positive or negative even is that it can wear your tires more. some cambers work well for straight lines and some for turns. i just think stock is the best for our cars for daily driving.
Sure is on Camber, but not on Caster, extra positive caster up to about 6* positive I am told is very good for high speed stability. Most luxury cars have that much positive caster or maybe more stock, Mercedes I hear is a good example. The guy set it on my V6 at 8* positive, but I was told that was too much, not sure what the disadvantage in it was, it did great on the highway, and handled fine in the curves. On The Camber thing, yes again, stock unless you are into auto cross or track racing maybe, then you should mark stock on your plates and move it back after the race.
I managed 45k from a set of protenza RE730 275/40/17s with a 1.25 inch drop and stock CC plates if you get it aligned to stock spec and rotate yoru tires EVERY 3k miles and align every 6k or more if you drive on alot of bumpy roads and crap your tires will last tons longer, OH and alwasy keep the air pressure where it should be.