The Ar 234A with its Jettisoning takeoff undercarriage was 20mph faster than the Ar 234B which had a retractable one. The B version had to be widened by 40mm to restore fuel capacity.
That gives an idea of the impact of undercarriage weight and space.
For the Luftwaffe the operational issue was that the 10 extra minutes it took to recover a landed Ar 234A (it couldn't taxi) left the aircraft too vulnerable to straffing and I suspect it took up too much runway time.
