[strat61caster]

CSG Spec Teins will be decent for autox, spring rates are in the ballpark for stiffness (but you'll be sacrificing comfort vs a softer coilover), camber plates will be necessary for using those big tires you paid a few hundred bucks for (I'd suggest -3.5 front camber as a starting point if you're serious about putting up good numbers for autox) and yes you'll need a lower control arm to get the rear camber adjusted, get the cheap SPC arm, no reason to spend more money, some of the fastest cars are using it (-2.5 degrees to start imho). Zero toe front, some toe in rear to taste.

There's a bunch of other advice to spout, but talk to your local STX drivers, ask questions, most autoxers are helpful. There's also tons of information to read up on if you're patient enough to search for it. It sounds like stock suspension likely fits your needs better but what the hell dive on in, it's a hobby.

Oh and nothing is illegal about your wheel and spacer setup for STX. There are alternative coilovers if you're willing to up the budget, but for ~$1.4k I don't think you'll find anything significantly better.