Very good points on the interior and firewall pad. It also deserves white walls in my opinion. However, because it is MB Classic they used what they furnish to customers. MB does not offer the diamond firewall pad.
Aside of this the asking price naturally reflects the over investment cost say$50,000 for the car and $200,000 for the restoration. That being said it is as nice as they come.
Back to my theory that the 230SL is the "purist's Pagoda" I foresee pricing between the 230SL and 280SL to be more similar moving forward.
What is more important to each individual buyer, the original design (no marker lights, beauty rims with rings, all of the extra chrome detail, no headrests, a specialized unique engine, no extras, no add ons) or the last of the line with larger engine and 4 wheel disc brakes.
I have felt that the historical greater demand for the 280SL also includes a factor of buyers that want original high quality unrestored newer examples. It is easier to find high quality original 280SL's than it is 230SL's, thus higher selling price based on condition.
This 230SL at Classic would be a great one to park in your dream checker floored garage floor or in your living room. Very high quality needing a few details to make for a restored perfect car. Too nice to drive.