GScholz, if you want to know wether the improved Mk108 saw service, your best bet would be Tony Williams, who sometimes posts here, but also has his own website and forum:
http://www.quarry.nildram.co.uk/The forum is linked from the main page.
F4UDOA, I'm sure Isegrim can post one. I'm also sure Nashwan and MiloMoron will attack him viciously and this thread will become a 500 post monster of mudslinging.
Firstly, I have never seen Isegrim post the information he says he has on 109K4 speed. I have seen other people I trust allude to it though, and because of that I'm prepared to accept there is some basis in fact. The only thing I've seen Isegrim post is his own graph comparing the K4 to whatever other aircraft he wants to disparage at the time.
As to attacking Isegrim, if you look at the thread you are reffering to, I pointed out (politely) that Isegrim was using power settings that weren't available until March 45 (iirc) and Isegrim responded by calling me a liar and accusing me of making up facts.
I'm prepared to give anyone another chance, and that includes Isegrim. If I get in another debate with him, then as long as he keeps it civil I will do the same.