If you plan on putting some good hard miles on it then I would say changing up the trans fluid with some fresh stuff is a wise investment. I did a little bit of of looking around, the scheduled maintenance for a 2001 XKR doesn't stipulate an interval for the trans fluid(sealed for life). For the Mercedes 5 speed w/4.0 liter SC it shows the fluid as being a Shell ATF 3403 M115 and part number JLM 20292 with a quantity of 9.5 litres (10.0 US quarts). If you can get it changed for £100 with proper parts then that is a pretty good deal, labour rate for drain and fill with filter change is 1.3 plus parts. JagRoverKid