doyle- bravo, your knowledge always impresses me, you are a true asset to this forum.
OP- here's my two cents: I drive my 3er mostly on the street, with a few track events a year. it's not my track duty car. It won't see serious track abuse so i never deemed it necessary to build it into a track car, just a car that can get around a track if i want it to. if you're a seasoned track driver, you'll realize this car isn't exactly the best platform from the get go to build a dedicated track car upon- although it's not impossible. through a member here, i went with the HPA kit with adj rears, which imho is the better buy, includes the coveted swift upgrade. i wanted the externally adj. rears, thrust sheets, camber plates, bushings, etc-- because i know the car will see at least one track day this month and while its apart, its probably more cost effective for me to have everything upgraded and overhauled at the same time. you don't necessarily "need" any of these upgrades but again..subjective. take your car to the track? go ext adj and camber plates, you'll want them. the spring rates for me wil be the "recommended" rates, a topic of which i won't touch with a twenty foot pole. When they go in, i will give it a week and write a review including my personal impressions of the kit. i've roadtested the TCK KIT, and well..it's fantastic, so i wonder how much better the HPA kit will feel. if you want to wait until then..but i won't make you. there's tons of great info here, doyle covered basically everything. make a decision based on your needs and the way you drive your car