i'm having the exact same problem. you can't automatically assume its the lifter...
however, it is worth it to flush the oil using a treatment. In my case we put a liter of diesel fuel and let the engine run for about half an hour before flushing it out. If it is a sticky lifter, the morning after you do this treatment, you should notice a difference.
Have you had a compression test done at cold?
In my case, i changed the coil on the misfiring cylinder, changed the spark plugs..... nothing. I then brought to a stealership, and they diagnosed the problem to be a cracked crankcase and faulty vent valve... Still did not help the problem... After this I tried the diesel treatment... but nothing changed.
I then brought the car to a trusted head machanic at another dealership, and he reprogrammed my DME. It now seems to be working better. I still get a little shake at cold start, and in 2 weeks, got only 1 misfire. It seems more intermitaent now, whereas it was every morning before.
Finally, i've decided to lay off it for a while and see if the problem becomes more significant, i.e. decrease in performance or worse symptom during cold start.
Let me know if you have further developements, and i will do the same.