Welcome to the Yacht Club! I recently traded an 84 300SD for a 90 300SE and I love it!
In my opinion, it's the best choice of the 126 class. Beautiful styling, combined with the reliability of the 103 workhorse engine. Smooth and quiet. Some would argue it's underpowered, they may be right. However, coming from a diesel, it's a screamer.
Here's wishing you many safe and enjoyable miles and hours of cruising.
84 300SD (sold)