I still don't know much about In Flames. Everyone seems to tell me that Clayman on up is where the downfall of the band takes place. The only album I own by them is Whoracle and I love it. Great melodic death metal.
As far as your other question goes... cduniverse.com is a great place to order from. I just recently placed an order from there consisting of the classics "Refuge Denied" by Sanctuary, "A Distant Thunder" by Helstar, and "Act III" by Death Angel and all went well. The End is indeed another great place to order from.
As far as German speed/power metal bands go you absolutely cannot go wrong with Running Wild, Grave Digger, Rage, Sinner, and Gamma Ray. Edguy is also really worth checking out if you have not heard them yet.