I've tried the WW with about 70%/30% mixture of antifreeze/water with good results.
With A/C on and hot day (90F), temp stays below 100 C. Also have the "Aux Fan mod" which does turn the fans on earlier so that mitigates this response. The fans do help a lot.
But if you are going to do a lot of desert driving, looks like it couldn't hurt. Based on the WW site info, you should be able to remove about 30-45 deg F of heat with 70/30 mixture. Even better if the antifreeze is 'old'.
Regards . . . . JimF
'94 S500 Cpe
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