Congrats on the 69. In my opinion that was the best year for the 280SL. It had head rests that the 68 didn't and didn't have the overheating and cylinder head problems of the 70 and 71 series. I know I'm not Arthur who seems very knowledgeable about the 113 series, but I would say stick with original. That car tachs 3600 rpms at 65 mph, and if you didn't put a cheap exhaust on it, it sounds beautiful on the open road. Changing to other tires may cause both clearance and power problems. I have a 67 230SL and a 71 280SL. We love to go camping with our 230SL. We have taken that car into some rugged areas and ito the mountains, and it has performed well. I find it to equal the 280SL.
Auto Zentral Ltd.