Tischer has the parts for $1705. I have a hard time figuring out complete system prices from the HPAutowerks site, but what you want is either the AST or Koni systems w/ Swift springs & rear lower camber link kit and I think you are around 5k including the M3 parts from Tischer. If you can get the TCKs instead and keep your costs under 3k that is awesome. I think it is critical to get the lot as a complete system, no weak links. Expect at least 1k for install. $ well spent IMO.
I have all the M3 parts except the rear camber link, BMW Perf dampers & springs, and just a 14mm rear sway. It is an OK system for the street, I was on a budget and the total for parts and install was well under 3k.
I have a hard time figuring out "value" for mods. To do things right you need about 7k for the engine (FMIC, BMW Perf kit, flash or piggy, DPs, exhaust), 4-7k for suspension, 4 or 5k for forged wheels and extreme non-rfts, 2-3k for LSD, and whatever you want for body/interior and brakes. So one could easily take a 45k 335 and end up with a 70k beast. Crazy.