I did it once but it was on the 83 Citation that I had owned. It had brown vinyl seats. I switched it out with a grey cloth interior. It took the better part of a day for the interior work alone, but after repainting the exterior to match, it looked good. I started with an all brown car in and out, and ended up with a dark red exterior with a charcoal grey interior. It was a sharp looking car when it was all done. Dash was a pain, and will take at least two people to line it up and one to crawl under and bolt it down. If you aren't mechanically minded leave it to the professionals. My brother and I did this, but we already had experience swapping engines, changing clutches, and we did more than one head gasket job.