I replaced the idle rack adjustment bolt on my IP for my '83 300SD, and I think it _somewhat_ helps with being a tad bit smoother idle (doesn't wander anymore), but it's still pretty rough. So what next?

I got a replacement timing belt tensioner spring (yet to be installed), as I changed the gasket a while back and I may have experienced some increased vibration after such.

The compression isn't ideal, one cylinder is around 290 psi I believe, the rest are at 320+ psi. I recently did a valve adjustment twice (maybe worth checking yet again). But I'm not sure if that would cause a noticeable vibration/shaking. It's been warming up recently and I'm afraid it will still exhibit that even when it's 60 degrees outside.

The injectors are definitely worn. I have a replacement Monarck set. I don't have any money to put toward the car any time soon (hoping to sell the car even though I know it needs lots of work, I will do what I can without $$), but I can at least replace the injector tips (using the same shims) and see if the shaking improves at all. Obviously it's a shot in the dark without getting the injectors balanced, but I don't have $100 for the tool or a shop to do it. I thought given the grim situation that at least trying at first might improve it somewhat, as long as I keep the injector internals the same and just replace the nozzles. I know that's just a shot in the dark.

The simplest adjustment seems to be the idle screw. I don't think that was ever adjusted, because it's on extremely tight. Beyond that, though, is there anything else obvious that is within my control? Any adjustments on the IP? The ALDA? Is it possible that the timing chain is stretched and can be adjusted/tightened somehow? Some sort of rundown of easiest to hardest adjustments/replacements would be helpful.

Thanks!