BMW E46 328Ci: Bilstein PSSS9 coilovers, UUC sway and strut bars, Michelin PS2 tires, UUC short shifter, Stewart waterpump, larger, update control arm bushings and arms, Bavarian Soundwerks Stage 1 speaker upgrades, Beisan VANOS seals, ATE brake fluid, and some random low-dust brake pads from BavAuto, DICE iPod interface.
Porsche Cayman: Borla exhaust, Porsche Motorsport throttle body/plenum, Softronic engine software, B&M short shifter, Conti ExtremeSport DWS tires, ATE brake fluid, Dension iPod interface. Traqmate data acquisition for track days.
Thinking about adding a double-DIN headunit for a better iPod integration in both cars, but otherwise pretty happy with them right now. The Cayman does track duty, while the BMW used to, but is mainly a street car these days.