Im looking for car parts and I wanted to now what years Buick I can use.
How do you know this?2000-2005 for most items on the body and interior. Mechanical items go further back to 1996 or so when OBD II diagnostics were first implemented.
But be careful of the radio and some other system components which changed year-to-year and are NOT interchangeable (not always obvious, either). Also, some of the electronic modules have the vehicle VIN coded into them, so forget about trying to swap junkyard modules in (some you can't at all like with the airbag SDM, and some you can like the radio, if you have a dealer with the GM scantool reprogram it).
Also, watch out for your wheel size. If your car came stock with 16" wheels (and larger brakes), you CAN'T use 15" wheels (even if they came off of the SAME YEAR of Lesabre), ask me how I know this!