MVVS, Pé Reivers, Irvine and many ppl can say whatever the hell they want... when there's metal chips in your engine there will be damage when you run it... And there were metal chips in 4 of the 5 MVVS's I have.
Even all threaded holes must be cleaned thoroughly, because the threads get messed up because of all the dirt in there. It appears the people at MVVS just tap the holes, and that's that... no cleaning or oil needed before the screws go in...
I'm really starting to like MVVS's, they're great little engines... but the dirty engines is really something they should work on.

It is better to dismantle a new engine than one that has been run.

Take a look at Metkemeijers website... especially the "cleaning" part...
[link=http://home.kabelfoon.nl/~fiorimet/Index.htm]Fiori metaal[/link]

They even use ultrasonic cleaners... you think it's clean? Well think (and clean) again... that's his motto. And he's right, the only things belonging in an engine are fuel and air... all the rest equals wear, performance loss and/or damage.

Now I'm not saying you need an ultrasonic cleaner to maintain your engines (pylon guys always go overboard ), but just giving all parts a good wash (or two) is the least one can do.
Look at the good side: it's little trouble and it might save you some bucks.