Many people have been burned by coupes that have been converted. Pun intended. You can take a 5k coupe, and make it a 20k cabrio, much more, if it is a low grill model like the 3.5 in question.

The real sad part is that there are many of these conversions out there, unkown to many buyers and some sellers. They are dangerous, because they lack the reinforced undercarriage that the cabrio models have.

The fire was probably caused by leaking rubber fuel injector fuel hoses, used on D-jet injection M117 and M116 v-8 models until 1975.