Lots of negotiating power with the SL all based on history at around 100k the timing chain should be changed? Gearbox service? Diff service
The timing chain and guides can all be done with the engine in the car and from the top (2 special tools but I hired them when I did it) Dealer told me impossible had to be front off the car or engine out he quoted £2.5k in 2005. It took me a Saturday but taking my time.
So if the dealer isn't a specialist, you may be able to worry him into a significant price drop.
Good luck if the Chancellor is happy you're moving in the right direction
Dave