There is no doubt that having a soft top makes a difference both in price and convenience. I like my Coupe and won't cut up the car to install a rag top. I have taken many day trips without the hard top and I am perfectly happy to drive showing off the Pagoda top. However, I have three other convertibles to choose from if I want to go overnight.
The SL letter puts something like a $4,000 value on the drop top. $16K is a great price for a rust-free, low-mileage edition. That is, if you can document the mileage. It is still a good price if it's in great shape and has 170,000 miles. In my opinion, once a car is over 15 years old, unless you want it for a garage queen, the mileage doesn't matter. If you are going to drive it, then the quality of its condition is far more important than the odometer. My car has 180,000 miles and my only interest in the odometer is tracking the lubrication maintenance schedule.
If you buy the car for $16K, spend $3-4K for parts, spend another chunk for the cutting, and finishing, what will it look like, and what have you done to any value the originality of the paint and 70K miles might have had?
Ray
'68 280SL 4-spd Coupe