Thanks 32. I thought the SLK had 17's, and figured I could go to 17s front and 18s rear and they would fit the XF. I know they have to clear the calipers too, and would need spacers for offset. I'm trying to put all this together to do it right and not make a big and expensive mistake. Also, I'd go with taller tires in an effort to maintain as closely as possible to original ride height so it doesn't throw off the speedo and odo calibrations. I think adding a half inch of sidewall all the way around would make a noticeable difference.


But if I can gain some ride comfort with SLK shocks and springs, without having to modify suspension mountings connections etc, I might want to try that first before I mess with the look and stance of the car, as you suggest.


Any idea how I can verify the specific differences in SLK springs shocks to determine how much comparative "smoothness" that would gain over the stock XF shocks and springs? I know there are specs such as spring rates and shock dampening rates, but how do you find out what the specific ratings are for each cars spring/shock combo, and then if there are differences in the rates, how do you interpret the data about the rates to determine which would result in the smoother ride?


I'd rather not go through all the trouble to swap springs and shocks and then afterward find out there is little or no difference.