Complex sentence: Despite Germany's reorganization, their manpower was still incomparable to that of the Western Allies; although Germany's Army Group B was able to increase their armored strength from 100 to 239 vehicles, these were opposed by 2,300 Allied tanks.
Split into simpler sentences: Despite Germany's reorganization, their manpower was still incomparable to that of the Western Allies. While Germany's Army Group B was able to increase their armored strength from 100 to 239 vehicles, these were opposed by 2,300 Allied tanks.