It is very easy is a if you don't have a 8 lung nut wheels you don't have lt . The f7 is heavy duty they were made for limo hearse and some dts L. OR long wheel base. If are think of buy it don't do it
You find out what's built into THAT car by looking at the RPO (Regular Production Option) sticker under the spare tire cover. Take a closeup digital picture, zoom it, print it, and Google "cadillac dts 2006 rpo codes" or something close.