I have an 08 Mazdaspeed 3 that I autocross. The car is also my daily driver. Right now it has a stock alignment. My camber isn't adjustable, but I figure I could switch to a zero-toe alignment without ruining the daily drive-ability. I'm just not sure if messing with the alignment is worthwhile at all. What type of time gain would we be talking about on a typical 60 second course? Is it seconds, tenths, or only hundredths? Any input would be appreciated.
Every adjustment towards performance can improve your time, but I think you should ask yourself if you heave the time and resources to make the adjustments.
You obviously have the time. You're messing around with your pressure. 
If you have the cash to drop into it, why not? The time is really going to depemd on how perfect you get the camber. No one can make any guarantees on your car, but Keith will probably have the best idea. Hint hint.
Look into camber bolts, they're worth it, both for tire wear and grip. Make sure you adjust toe. I'm very slightly toe out on the mazda2 and the difference was very noticeable. It's hard to say how much time you'll get. With just the camber and toe change and a practice event with 35 or so runs to really get a feel for the car I went from 5 seconds back (same at two events) to 1.5 seconds back of a new friend. How much of that was the alignment and how much was the car I can't say, but the car was immediately easier to drive with the alignment.
Keep in mind those camber bolts also push you into a higher class.
By loosening ALL of the mounting bolts, some camber can be gained from play in the mounts Be sure and reset the toe after.
http://www.tirerack.com/suspension/suspension.jsp?make=Eibach&model=Recommended+Align.+Kit&group=Recommended+Align.+Kit&partNum=5.67420K&autoMake=Mazda&autoModel=MazdaSpeed3&autoYear=2008&autoModClar=
You can get some adjustment in camber. (edit.. thats rear... opps)
If there is a factory kit that is in the factory service manual for crash repairs, that factory kit is stock legal.
What class?
You are talking a decent time gain, likely in the multiple tenths range. (huge in autocross terms) The larger thing really is that your tires will last longer due to even wear.
Glad to see you're not in the StL area. Your handle scares me.
I found that zero toe or toe-out on a FWD car makes a huge difference in handling. Way more responsive to steering inputs and helps induce oversteer to rotate a nose heavy pig.
I used to run zero toe on the street and just make a quick toe-out adjustment at the track and adjust back for the drive home. It's pretty easy if you only adjust one tie rod at the track too. That way you know it went back to zero if the steering wheel is straight on the commute back.
I race a C-stock RX8 in the local SCCA chapter. Last season I ran about 1.2 degrees of camber front and back and zero toe. This season I'm running almost 3 degrees of camber up front and 1.5 in the back, with 1/16" toe out (I adjust toe the night before the event so I don't wear tires). I'd say on average I picked up around 0.4-0.5 seconds on a 40 second course with the change in alignment.
The more camber you can get (within reason), the better for steady-state cornering (more ultimate traction). The toe serves to "pre-load" the tires by creating some slip angle even before you turn the wheels. This gives you much quicker response at turn-in, but doesn't increase ultimate traction much, if at all. Both should help you pick up time in an autocross setting.
What JohnyHachi6 said....
Several Miata guys in Denver would add .38" of toeout to their cars prior to running, then dial it back prior to driving home.
Most of these drivers would rave about the improved turn in....
Rog
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