I want to buy a 2006 SL 500
I bought a 2006 SL 500 a little over two years ago. It was from a MB dealer and Certified Pre-Owned by MB. It only had about 16k miles on it then and now I am up to about 53k. Bought an extended warranty from MB, underwritten by National Warranty Corporation. You can negotiate the price for these warranties. Most routine work (brakes, oil, filters, plugs) is done by an independent shop who I have known for years, they worked on my far from stock BMW without any issues and thier labor costs are $30 less per hour than the dealer, plus I really trust the guys, 2 older German brothers and they really care about cars. I really love the car, great styling but I have read too many horror stories on this site (which by the way is an excellent resource) to go without an extended warranty which will cover me until 2/11/15 or 85k miles whichever comes fiirst. So far, brakes done at about 24K miles (ceramic pads reduced brake dust by 90%), malfunctioning transmission valve caused hard downshift mainly when cold -replaced by MB under original warranty. Leaky valve cover gaskets, covered by the extended warranty ($350), and the all too common flaps on the boot cover (terrible engineering and cheap plastic), considered a trim piece and not covered by extended warranty. I am having some aluminum hinges fabricated to solve this problem as I refuse to pay MB $400 for the part only for it to probably fail again, shame MB for this part, its design and refusal to admit to their poor design. MB should offer repair at cost due to systemic problem, but first they would have to admit there was a problem, good luck with this. The care is great fun to drive (silver with red interior, AMG appearance group), top down whenever possible. Love the Pano roof, gives me at 6'3" a bit more head room and does not feel as claustrophobic as the metal roof.
I don't know how many miles I would feel comfortable with but I would heed all of the repair estimates and threads on this site. It is an expensive car and consequently expensive to maintian and repair, but unless you go really exotic, it's hard to beat the styling and comfort. Good luck.