Thanks gents, for all the info.
I have also found some interesting things.
The Roden (models) website had some useful background information about the various 8-rads.
Info from a Roden kit about the Sdkfz 232 (8-rad):
"War against the Soviet Union was a severe test for eight-wheeled armored vehicles - in autumn Russia's vast territory was a total mash of mud and heavy cars of the 8-Rad type turned out to be especially vulnerable in this environment. During the first half year of operations about 150 eight-wheeled cars were destroyed. In North Africa the Sd.Kfz. 232 (Fu) (8-Rad) served as a part of the African Corps under the command of Erwin Rommel. High air temperature was one of the most significant problems for armored cars and tanks, since due to tough climatic conditions technical failures were frequent. Eight-wheeled cars turned out to be the best vehicles for long raids in wide desert territory and were in service almost until the last days of DAK existence.
Sd.Kfz 232 (Fu) (8-Rad) production was stopped in 1943 when the Sd.Kfz 234 appeared, the glorious "Puma", the best armored car of WWII, which surpassed the Sd.Kfz 232 (Fu) (8-Rad) in every aspect of performance. Some of the Sd.Kfz. 232 (Fu) (8-Rad) were upgraded to a gun version, the Sd.Kfz 233 "Stummel", while others were upgraded with new radio communication equipment and returned to the front where they continued their military service. Several Sd.Kfz 232 (Fu) (8-Rad) fought for Berlin at the beginning of May 1945 during the severe street fights in the German capital - and as true soldiers they fought against the enemy until the end."
From another kit - 234/1, note low production total:
"Most of the 200 Sd.Kfz 234/1 produced up to the beginning of 1945 were sent to the Western Front and they fought there in the last battles of WWII."
Info from a Roden kit about the 234/3:
"Batch production began at the end of 1943 and continued up to the end of 1944. In total there was the opportunity to build only 88 units of the Sd.Kfz.234/3, as in 1944 the German war industry experienced widespread destruction from Allied bombing strikes, and any areas which had escaped, directed their efforts towards repairing the damage of existing armor and equipment."
The overwhelming majority of the 88 completed Sd.Kfz.234/3 served with the 116th Panzer Division which was at war in Normandy. "
Finally, this about the Puma:
"In 1943 the situation on the battlefield took a crucial turn, but not in the Germans' favor. German armored cars were being destroyed in combat; meanwhile the army required a large output of new tanks. Plants manufacturing the old Sd.Kfz.232 (8-Rad) armored car were not able to immediately switch production facilities to production of a new model. All of this became a serious obstacle for Sd.Kfz.234/2 (later nicknamed the Puma) production. The initial plan was to produce at least 80 cars per month by mid 1943, however this was never realized.
The Sd.Kfz.234/2 Puma had little in common with its predecessor. It was similar in concept but overall a completely new car. The powerful high-rotation Tatra 103 engine (eventually brought to operational reliability) allowed this armored car to make 90 km/h, and the huge 360 liter fuel tank increased its range to 1000 km. The Puma was the heaviest armored car of WWII, weighing over 11 tones. In comparison with the older Sd.Kfz.232 (8-Rad) cars the Puma had been slimmed down, particularly in respect of ground clearance, according to requirements. The Puma was armed with a 50-mm KwK39/1 gun with full 360 degree rotation, installed so as to allow a good vertical arc of fire. The armored body was several times thicker in comparison with the Sd.Kfz.232 (8-Rad), especially in front.
Sd.Kfz.234/2 Puma production ran into difficulties and only a rather small number of them was produced, 101. Nevertheless they did fight during WWII, with the panzer divisions in Normandy. This impressive car had not realized its full capability, but its combat performance showed exciting potential. After tests in the British and USA ordnance yards it was judged by the Allies to be the best armored car of the WWII era."
Of course, we don't have access to the 234/4 in AK, but production total estimates range from 89-98.
It's clear to me that the TOEs are extremely optomistic and the production totals don't match up very well. It also seems clear that the under-powered engine in all the 8-rads meant that they weren't nearly as mobile in muddy terrain. The 250/9s were brought in to replace the 222s and supplement the 8-rads. But since the production of the 234 models was so slow, the remaining earlier 8-rads were kept going as long as possible, sometimes apparently by recycling old parts into newer models.
Of course, as a CM'r I abhor the the light ammo load of the 250/9, and even the PSWs, while loving the generous loadout of the 251/17. Sigh. Does that make me "gamey"?