wobbles swapped the air filter for a pipercross panel filter. Didn't notice any difference, started to sound a bit different though. The diesel ticking sounds more mellow, or more bright to be honest. The high midrange frequency and seem to find it's way through any sound proofing seems less noticeable. So in the cab it sounds less annoying and more... modern I guess. At least I find newer diesel engines to have a higher frequency/more trebly sounding tick. So happy with it but I can't say it did much for power
I fitted the blanking plate yesterday. Didn't notice much of a difference in the engine light, I stays on maybe 1 second longer when you start the van but nothing that one pays attention to. It was pitch dark so I can't say anything about smoke just yet. Went for a short drive to see if it felt different and it sure did. Wasn't a mind blowing difference at all but when accelerating it felt more direct and like a more energetic engine. So all good and happy with the results for such a simple mod!
Worth noting though is that mine didn't have much gunk and soot in the pipes from what I could see. I expected a lot from reading around, but it was more like a fine 0.5-1mm layer of soot in the pipes. I guess if you have a gunked up engine you might notice quite a bit more difference than what I did.
Going for a longer 500km drive during the weekend so still waiting to see how it feels when doing 80-100km/h for longer periods.