I gave mine to a friend of a friend who runs a big insurance repair centre. He had the 123 for about 3 months, (did in spare time) but he did a very good job; completely stripped, new front and rear ends, 3 new doors, one wing, lots of bits and complete rustproofing, all for about 1800 inc.... 2 yrs later and no sign of bubbles or rust....
Therefore keep asking around, if you take to an insurance type place, youll need to remortgage...And besides, you dont want to spoil the original paintwork on a 96 merc.....