Hey guys, Sorry to bring up this old post.
I have the same problem with the SAI system. Both P1410 and 1411 codes are on. The OEM check valve and change over valves are expensive.
Particlewave, I know you confirmed the Mercedes MTC3095 was a perfect fit for the check value in 986. Can you confirm if the mercedes part for the change over value is also a good fit? The part looks different. How did you make it fit? Do you have pictures you can share?
NEW MERCEDES AIR VALVE 380SLC 380SEL 380SL 380SEC 420SEL 190E OE # 000-140-77-60 | eBay
Also, any update on your little hack on fooling the DME during cold starts? do you have it up and running?