Depends on which parts... I usually buy manufacturer direct except for the electronics stuff because I'm reliant upon specialists for those types of things... Lloyd at TunerTools is the specialist in that department... I'm still a NEWBIE when it come to these darned car computers... Gimme a distributor cap, timing light and screwdriver and I'm in my safety zone... But I'm learning way too much stuff now and it's starting to scare me...