It is not a good price if you waste $1K getting it removed a week after you install it! That is obviously what the original owner did. At that point, you've spent $1200 and gained nothing but a headache. Have you considered why this almost new aftermarket clutch assembly is for sale?
Such an E39 240mm clutch & aluminum flywheel combo is classified as "featherweight". It offers only cons for a street M5. That kit belongs in a 150 HP Pinto or Formula Ford used for SCCA racing. The clutch may be weak as stock (or obsolete weaker design) and the tiny featherweight race flywheel assembly will likely rattle until you can't stand it any longer. The mfg build date and other things are critical. The earlier SAC clutch designs were factory defective and some are sitting in dusty garages on shelves. Used SAC clutches must be reset with a complicated dealer-only tool, if the clutch disc is not matched to the pressure plate. Since you have no evidence this is a matched clutch set & it's used, there is risk. This setup is not a suitable kit for a 400 HP $75K 4dr sedan.