You need to do the tires and wheels before you mess up one of those expensive 19"wheels. I love the Apex wheels for the weight savings and price. Go with the square setup. You need better street tires like NT05 or RS3. I run PF01s on my Stoptechs and they have a great bite.
I plan to do camber plates and seats next. I am considering Recaro Sportster CS since they will fit my big frame better.
I would spend some money on data acquisition so you can track your progress.