I buy most of my mods used. So many people sell barely used parts because they want to try something different or upgrade to a new car. I also sell my cars stock and part-out the mods separately. It's still expensive but the cost is minimized with this approach. I have been lucky enough to sell some parts for the same price I paid for them.
KW Clubsport 3-way, Akrapovic Evolution, ESS Tune, StopTech Trophy, IND Euro Bumper & Black Mirror Covers, Turner Motorsports Studs/Lugs & Delrin Diff Bushings, MRF Solid Sub-Frame Bushings, RD Sport Sways, Recaro Profi-XL & Planted Seat Brackets, BMW Performance Carbon Fiber Interior Trim, BMW Edition Grills/Gills, Mode Carbon GT4 Splitter & GTS Wing, Advan TC3 (18x9.5/10.5), BBS E05 (18x10/11), G-Force Rivals (275/295)