To Option or Not?

[S2KtoH3]

Okay here is the deal. I want to get a black on black with Luxury, Adventure and sunroof. I know those are all factory options and is how the car must be configured upon delivery. However, I also want to get the black crossbows, black tubular assist steps and the wrap-around brush gaurd. If I were to buy these accessories a la carte from a dealership, would it cost me more instead of having the car fitted with them at the factory? Second, would I be able to install it on my own. I'm fairly good with cars so I'll know what I'll be doing. But is it something that can even be done if it wasn't installed at the factory? Reason I ask is because I know I won't find a car local to me with the exact specs that I want. Chances are better though that I'll find a black/black with just lux, adventure and sunroof and then I can add the accessories myself. This way I can get a better deal on a car thats already on the lot rather than have to special order with the accessories that I want and possibly pay a premium. Thanks in advance.