I had the Falkens Azenis on my WRX and they really had amazing grip along with an unbeatable price for you bang. The downsides of these tires are the wear rating(not bad considering the price), road noise and not the most rain friendly thread pattern. Otherwise these honestly are nothing short of amazing "street tires". These tires perform really well on a Solo II type of course but in my experience they quickly become unpredictible and "greasy" once they reach a certain temps making them undesirable for open track or Solo I use.

Depending on your needs I would actually suggest comparing the Falkens with the Kuhmo MX. It has been my understanding that with the MX's the grip is very comparable to the Falkens while offering a more reaonable thread pattern and less road noise. These are a bit more expensive but I have a feeling these will be my next set of tires.

If you're "tracking it" you really need to research R compound tires. The Kuhmo Victorracers are a very popular afforable choice. These types of tires generaly unacceptable for street use due to wear, noise, stiffness, thread and pickup. There are a few R compound choices out that are "more streetable" but I doubt this is what you're looking for unless you're insane and rich. Seriously, I'm not just going on rant here and I doubt you will find a single professional that would advise such a setup on a street car.

I think springs are a poor choice w/o the appropriate struts unless more going for bling. I think you should start with a rear sway bar and endlinks and slowly work your way up while researching very carefully. Suspension can very tricky and expensive with disapointing results unless you know what you're doing and know exactly what you're looking to accomplish.

Also, you will seriously risk killing yourself with a roll cage in a daily driven car. This really is a VERY bad idea unless it's a dedicated track car driven to events on trailer. All it takes is small fender bender to send your head towards the roll cage without a helmet you're very likley to have serious head injuries. The padding will only help to soak up the blood. :o