I just put some on my 2 door. As the last post said you might need brackets. My 2 door did not have them on and I did not know out about the lack of brackets until after I bought the stock running boards off e-bay. I went to GM and bought new ones. About $97.00 with a discount. You will need more for a 4 door. The T-bolts cost $9.00 a peace and I was short 2 of the10. I then had bids of $100 to $200 to weld the brackets on. After looking the bracket over closely I bolted them on for about $15.00 and they work great. If you weld them you have wires and carpet to remove. The door kick plate has a hollow place under them and you can use nuts and bolts their. The other brackets I used large sheet metal screw with bolt heads. It you need more information just ask. It made the 2 door look nicer. Dave