The SL600's twin-turbocharged 5.5L V12 (cited at 493hp and 590 lb-ft) is treated as a special, increasingly scarce configuration. Clean low-mileage V12s are described as hard to find and appreciating, with a very-low-mileage 2004 selling for $43,250 and commenters noting the V12 market suddenly heating up while still representing a fraction of original MSRP.
SL600 twin-turbo V12: desirability and appreciation
Mercedes-Benz SL (R230) · market