What are the exact goals for the car? I can tell you right now if you want a successful platform for autox the 335i isnt going to compete well in any class. It can't fit enough tire, it's too heavy, and the competition is too high (STI, Evo, etc.)
Vorshlag camber plates have great reviews, generally favored by those doing double duty (street + track). Ground Control plates offer a wider range of settings but tend to be noisier.
If I were you I'd wait to do your suspension tuning all at once. Learn to drive the car as it is... Save money for disposables like tires, brakes, fluids etc. once you've got that figured out and it's truly the car that's holding you back then drop money on everything and tweak to your liking. If you're like me you'll realize the 335i isn't going to meet your goals and youll buy a dedicated car... If you're a junkie like me ;-)
1997 M3 Coupe - BMWCCA I-Prepared #22
2006 M Roadster - 23,000 miles and slowly counting