well the Ju88 was a 'schnell bomber' (sp?) and was meant to be faster than the Do/He (by around 30km/h iirc).
I agree the speeds i use are a little slow but i think most planes are a little slow and these speeds allow formation keeping without blowing engines and give me reasonable results in mission building.
Ju88 manual is in this little collection of pilot's notes
http://www.mediafire.com/download.php?jkxxvwayw9fqbk3