2003 Mercedes Benz Other Misfire

I have a Mercedes ClK W209 240, I had a ticking noise coming from front of engine for about a week now but my AC button light was stuck on, so thought might be a stepping motor, but I then went to overtake a car few days later and lost all power and the engine light came on and went into limp mode. I got car recovered, I then plugged it into my diagnostics and fault codes : PO305, PO306 and PO300 came up, so I thought I'd test the Coilpack by swapping cylinder 5 with cylinder 4s to see if the misfire moved, but it didn't, and now I only have one fault code, just PO305, I've had the spark plugs out cleaned them up and still misfiring. I'm pritty stumped now, the whole car shakes
and won't rev over 4000 and feels very strained, this shouts MAF sensor to me? Because when it did break down one of the intake pipes had popped off. So any help here would be great fully received. Before I start buying stuff I don't need. Cheers